diff --git a/apisix/cli/ops.lua b/apisix/cli/ops.lua
index 16547fce360c..e3af57c1c9b6 100644
--- a/apisix/cli/ops.lua
+++ b/apisix/cli/ops.lua
@@ -502,17 +502,34 @@ Please modify "admin_key" in conf/config.yaml .
 
 
     if yaml_conf.apisix.ssl.ssl_trusted_certificate ~= nil then
-        local cert_path = yaml_conf.apisix.ssl.ssl_trusted_certificate
-        -- During validation, the path is relative to PWD
-        -- When Nginx starts, the path is relative to conf
-        -- Therefore we need to check the absolute version instead
-        cert_path = pl_path.abspath(cert_path)
+        local cert_paths = {}
+        local ssl_certificates = yaml_conf.apisix.ssl.ssl_trusted_certificate
+        for cert_path in string.gmatch(ssl_certificates, '([^,]+)') do
+            cert_path = util.trim(cert_path)
+            if cert_path == "system" then
+                local trusted_certs_path, err = util.get_system_trusted_certs_filepath()
+                if not trusted_certs_path then
+                    util.die(err)
+                end
+                table.insert(cert_paths, trusted_certs_path)
+            else
+                -- During validation, the path is relative to PWD
+                -- When Nginx starts, the path is relative to conf
+                -- Therefore we need to check the absolute version instead
+                cert_path = pl_path.abspath(cert_path)
+
+                if not pl_path.exists(cert_path) then
+                    util.die("certificate path", cert_path, "doesn't exist\n")
+                end
 
-        if not pl_path.exists(cert_path) then
-            util.die("certificate path", cert_path, "doesn't exist\n")
+                table.insert(cert_paths, cert_path)
+            end
         end
 
-        yaml_conf.apisix.ssl.ssl_trusted_certificate = cert_path
+          local combined_cert_filepath = yaml_conf.apisix.ssl.ssl_trusted_combined_path or "/usr/local/apisix/conf/ssl_trusted_combined.pem"
+        util.gen_trusted_certs_combined_file(combined_cert_filepath, cert_paths)
+
+        yaml_conf.apisix.ssl.ssl_trusted_certificate = combined_cert_filepath
     end
 
     -- enable ssl with place holder crt&key
diff --git a/apisix/cli/schema.lua b/apisix/cli/schema.lua
index e6720f88fa2a..1def95484bcb 100644
--- a/apisix/cli/schema.lua
+++ b/apisix/cli/schema.lua
@@ -209,6 +209,9 @@ local config_schema = {
                         ssl_trusted_certificate = {
                             type = "string",
                         },
+                        ssl_trusted_combined_path = {
+                            type = "string",
+                        },
                         listen = {
                             type = "array",
                             items = {
diff --git a/apisix/cli/util.lua b/apisix/cli/util.lua
index bcd56a241aa8..c4f8825c527d 100644
--- a/apisix/cli/util.lua
+++ b/apisix/cli/util.lua
@@ -133,4 +133,44 @@ function _M.file_exists(file_path)
     return f ~= nil and close(f)
 end
 
+
+do
+    local trusted_certs_paths = {
+      "/etc/ssl/certs/ca-certificates.crt",                -- Debian/Ubuntu/Gentoo
+      "/etc/pki/tls/certs/ca-bundle.crt",                  -- Fedora/RHEL 6
+      "/etc/ssl/ca-bundle.pem",                            -- OpenSUSE
+      "/etc/pki/tls/cacert.pem",                           -- OpenELEC
+      "/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem", -- CentOS/RHEL 7
+      "/etc/ssl/cert.pem",                                 -- OpenBSD, Alpine
+    }
+
+    function _M.get_system_trusted_certs_filepath()
+      for _, path in ipairs(trusted_certs_paths) do
+          if _M.file_exists(path) then
+              return path
+          end
+      end
+
+      return nil,
+            "Could not find trusted certs file in " ..
+            "any of the `system`-predefined locations. " ..
+            "Please install a certs file there or set " ..
+            "`lua_ssl_trusted_certificate` to a " ..
+            "specific file path instead of `system`"
+    end
+end
+
+
+function _M.gen_trusted_certs_combined_file(combined_filepath, paths)
+    local combined_file = assert(io.open(combined_filepath, "w"))
+    for _, path in ipairs(paths) do
+        local cert_file = assert(io.open(path, "r"))
+        combined_file:write(cert_file:read("*a"))
+        combined_file:write("\n")
+        cert_file:close()
+    end
+    combined_file:close()
+end
+
+
 return _M
diff --git a/conf/config.yaml.example b/conf/config.yaml.example
index 44005ffd0fb7..ddf7f4691c0f 100644
--- a/conf/config.yaml.example
+++ b/conf/config.yaml.example
@@ -99,9 +99,9 @@ apisix:
       # - ip: 127.0.0.3                           # If not set, default to `0.0.0.0`.
       #   port: 9445
       #   enable_http3: true
-    # ssl_trusted_certificate: /path/to/ca-cert   # Set the path to CA certificates used to verify client
-                                                  # certificates in the PEM format.
-    ssl_protocols: TLSv1.2 TLSv1.3                # TLS versions supported.
+    ssl_trusted_combined_path: /usr/local/apisix/conf/ssl_trusted_combined.pem # All the trusted certificates will be combined into a single file
+    #ssl_trusted_certificate: system              # Specifies comma separated list of trusted CA. Value can be either "system"(for using system available ca certs) or
+                                                # a file path with trusted CA certificates in the PEM format
     ssl_ciphers: ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384
     ssl_session_tickets: false  # If true, session tickets are used for SSL/TLS connections.
                                 # Disabled by default because it renders Perfect Forward Secrecy (FPS)
diff --git a/t/cli/test_stream_config.sh b/t/cli/test_stream_config.sh
index baab138a0c99..2843b5c5d13a 100755
--- a/t/cli/test_stream_config.sh
+++ b/t/cli/test_stream_config.sh
@@ -78,6 +78,7 @@ echo "
 apisix:
     ssl:
         ssl_trusted_certificate: t/certs/mtls_ca.crt
+        ssl_trusted_combined_path: t/certs/mtls_ca_combined.crt
     proxy_mode: http&stream
     stream_proxy:
         tcp:
@@ -86,7 +87,7 @@ apisix:
 
 make init
 
-if ! grep "t/certs/mtls_ca.crt;" conf/nginx.conf > /dev/null; then
+if ! grep "t/certs/mtls_ca_combined.crt;" conf/nginx.conf > /dev/null; then
     echo "failed: failed to set trust certificate"
     exit 1
 fi
diff --git a/t/cli/test_upstream_mtls.sh b/t/cli/test_upstream_mtls.sh
index 0318a4539a27..b2b366aa0635 100755
--- a/t/cli/test_upstream_mtls.sh
+++ b/t/cli/test_upstream_mtls.sh
@@ -149,3 +149,63 @@ if ! grep -E 'self-signed certificate' logs/error.log; then
 fi
 
 echo "passed: when proxy_ssl_verify is enabled and ssl_trusted_certificate is wrong ca cert, got 502"
+
+
+#  test combined proxy_ssl_trusted_certificate success
+echo '
+apisix:
+  ssl:
+    ssl_trusted_certificate: system, t/certs/apisix.crt
+nginx_config:
+  http_configuration_snippet: |
+    server {
+        listen 1983 ssl;
+        server_name test.com;
+        ssl_certificate             ../t/certs/apisix.crt;
+        ssl_certificate_key         ../t/certs/apisix.key;
+        location /hello {
+            return 200 "hello world";
+        }
+    }
+  http_server_configuration_snippet: |
+    proxy_ssl_verify on;
+' > conf/config.yaml
+
+rm logs/error.log || true
+make init
+make run
+sleep 0.1
+
+curl -k -i http://127.0.0.1:9180/apisix/admin/routes/1 -H 'X-API-KEY: edd1c9f034335f136f87ad84b625c8f1' -X PUT -d '
+{
+    "uri": "/hello",
+    "upstream": {
+        "pass_host": "rewrite",
+        "nodes": {
+            "127.0.0.1:1983": 1
+        },
+        "scheme": "https",
+        "hash_on": "vars",
+        "upstream_host": "test.com",
+        "type": "roundrobin",
+        "tls": {
+            "client_cert": "-----BEGIN CERTIFICATE-----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\nU/OOcSRr39Kuis/JJ+DkgHYa/PWHZhnJQBxcqXXk1bJGw9BNbhM=\n-----END CERTIFICATE-----\n",
+            "client_key": "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"
+        }
+    }
+}'
+
+sleep 1
+
+code=$(curl -v -k -i -m 20 -o /dev/null -s -w %{http_code} http://127.0.0.1:9080/hello)
+
+if [ ! $code -eq 200 ]; then
+    echo "failed: connection to upstream with mTLS failed"
+    exit 1
+fi
+
+sleep 0.1
+
+make stop
+
+echo "passed: connection to upstream with mTLS success"