diff --git a/apisix/plugins/forward-auth.lua b/apisix/plugins/forward-auth.lua
index 39e690038890..6d4454a581e8 100644
--- a/apisix/plugins/forward-auth.lua
+++ b/apisix/plugins/forward-auth.lua
@@ -88,6 +88,9 @@ function _M.access(conf, ctx)
         ["X-Forwarded-Host"] = core.request.get_host(ctx),
         ["X-Forwarded-Uri"] = ctx.var.request_uri,
         ["X-Forwarded-For"] = core.request.get_remote_client_ip(ctx),
+        ["Expect"] = core.request.header(ctx, "expect"),
+        ["Content-Length"] = core.request.header(ctx, "content-length"),
+        ["Transfer-Encoding"] = core.request.header(ctx, "transfer-encoding")
     }
 
     -- append headers that need to be get from the client request header
@@ -106,8 +109,17 @@ function _M.access(conf, ctx)
         method = conf.request_method
     }
 
+    local httpc = http.new()
+    httpc:set_timeout(conf.timeout)
     if params.method == "POST" then
-        params.body = core.request.get_body()
+        local client_body_reader, err = httpc:get_client_body_reader()
+        if client_body_reader then
+            params.body = client_body_reader
+        else
+            core.log.warn("failed to get client_body_reader. err: ", err,
+            " using core.request.get_body() instead")
+            params.body = core.request.get_body()
+        end
     end
 
     if conf.keepalive then
@@ -115,9 +127,6 @@ function _M.access(conf, ctx)
         params.keepalive_pool = conf.keepalive_pool
     end
 
-    local httpc = http.new()
-    httpc:set_timeout(conf.timeout)
-
     local res, err = httpc:request_uri(conf.uri, params)
     if not res and conf.allow_degradation then
         return
diff --git a/t/plugin/forward-auth.t b/t/plugin/forward-auth.t
index 7896d4f84b74..356860e2adfd 100644
--- a/t/plugin/forward-auth.t
+++ b/t/plugin/forward-auth.t
@@ -130,6 +130,14 @@ property "request_method" validation failed: matches none of the enum values
                                                end
                                            end
                                         end
+                                    end]],
+                                    [[
+                                        -- test large body
+                                        return function(conf, ctx)
+                                        local core = require("apisix.core")
+                                        if core.request.get_method() == "POST" and core.request.header(ctx, "Authorization") == "large-body" then
+                                           core.response.exit(200)
+                                        end
                                     end]]
                                 }
                             }
@@ -254,6 +262,25 @@ property "request_method" validation failed: matches none of the enum values
                             "type": "roundrobin"
                         }
                     }]],
+                },
+                {
+                    url = "/apisix/admin/routes/7",
+                    data = [[{
+                        "plugins": {
+                            "forward-auth": {
+                                "uri": "http://127.0.0.1:1984/auth",
+                                "request_headers": ["Authorization"],
+                                "request_method": "POST"
+                            }
+                        },
+                        "upstream": {
+                            "nodes": {
+                                "127.0.0.1:1980": 1
+                            },
+                            "type": "roundrobin"
+                        },
+                        "uri": "/large-body"
+                    }]],
                 }
             }
 
@@ -266,7 +293,7 @@ property "request_method" validation failed: matches none of the enum values
         }
     }
 --- response_body eval
-"201passed\n" x 9
+"201passed\n" x 10
 
 
 
@@ -374,3 +401,41 @@ GET /hello
 --- more_headers
 Authorization: 111
 --- error_code: 200
+
+
+
+=== TEST 13: test large body
+--- config
+    location /t {
+        content_by_lua_block {
+            local t    = require("lib.test_admin")
+            local http = require("resty.http")
+            local httpc = http.new()
+
+            local tempFileName = os.tmpname()
+            local file = io.open(tempFileName, "wb")
+
+            local fileSizeInBytes = 11 * 1024 * 1024 -- 11MB
+            for i = 1, fileSizeInBytes do
+                file:write(string.char(0))
+            end
+            file:close()
+
+            local large_body = t.read_file(tempFileName)
+            local uri = "http://127.0.0.1:" .. ngx.var.server_port
+            .. "/large-body"
+            local res, err = httpc:request_uri(uri,
+                {
+                    method = "POST",
+                    body = large_body,
+                    headers = {
+                        ["Authorization"] = "large-body",
+                        ["Content-Type"] = "application/x-www-form-urlencoded"
+                    }
+                }
+            )
+
+            ngx.say(res.body)
+        }
+    }
+--- error_code: 200