diff --git a/apps/emqx_bridge_s3/src/emqx_bridge_s3_upload.erl b/apps/emqx_bridge_s3/src/emqx_bridge_s3_upload.erl
index c1a6ee6f7..00fd6fdc0 100644
--- a/apps/emqx_bridge_s3/src/emqx_bridge_s3_upload.erl
+++ b/apps/emqx_bridge_s3/src/emqx_bridge_s3_upload.erl
@@ -69,7 +69,11 @@ fields(?ACTION) ->
             }),
             #{
                 required => true,
-                desc => ?DESC(s3_upload)
+                desc => ?DESC(s3_upload),
+                %% NOTE
+                %% There seems to be no way to attach validators to union types, thus we
+                %% have to attach a "common denominator" validator here.
+                validator => validators(s3_upload_parameters)
             }
         ),
         #{
@@ -211,6 +215,9 @@ desc(s3_upload_resource_opts) ->
 desc(_Name) ->
     undefined.
 
+validators(s3_upload_parameters) ->
+    emqx_s3_schema:validators(s3_uploader).
+
 convert_actions(Conf = #{}, Opts) ->
     maps:map(fun(_Name, ConfAction) -> convert_action(ConfAction, Opts) end, Conf);
 convert_actions(undefined, _) ->
diff --git a/apps/emqx_bridge_s3/test/emqx_bridge_s3_aggreg_upload_SUITE.erl b/apps/emqx_bridge_s3/test/emqx_bridge_s3_aggreg_upload_SUITE.erl
index 538e7b306..09cf12329 100644
--- a/apps/emqx_bridge_s3/test/emqx_bridge_s3_aggreg_upload_SUITE.erl
+++ b/apps/emqx_bridge_s3/test/emqx_bridge_s3_aggreg_upload_SUITE.erl
@@ -156,6 +156,24 @@ t_create_via_http(Config) ->
 t_on_get_status(Config) ->
     emqx_bridge_v2_testlib:t_on_get_status(Config, #{}).
 
+t_invalid_config(Config) ->
+    ?assertMatch(
+        {error,
+            {_Status, _, #{
+                <<"code">> := <<"BAD_REQUEST">>,
+                <<"message">> := #{<<"kind">> := <<"validation_error">>}
+            }}},
+        emqx_bridge_v2_testlib:create_bridge_api(
+            Config,
+            _Overrides = #{
+                <<"parameters">> => #{
+                    <<"min_part_size">> => <<"5GB">>,
+                    <<"max_part_size">> => <<"100MB">>
+                }
+            }
+        )
+    ).
+
 t_aggreg_upload(Config) ->
     Bucket = ?config(s3_bucket, Config),
     BridgeName = ?config(bridge_name, Config),
diff --git a/apps/emqx_s3/src/emqx_s3_schema.erl b/apps/emqx_s3/src/emqx_s3_schema.erl
index 1fa6d31cd..efef32aa0 100644
--- a/apps/emqx_s3/src/emqx_s3_schema.erl
+++ b/apps/emqx_s3/src/emqx_s3_schema.erl
@@ -10,6 +10,7 @@
 -import(hoconsc, [mk/2, ref/2]).
 
 -export([roots/0, fields/1, namespace/0, tags/0, desc/1]).
+-export([validators/1]).
 
 -export([translate/1]).
 -export([translate/2]).
@@ -177,6 +178,14 @@ desc(s3_upload) ->
 desc(transport_options) ->
     "Options for the HTTP transport layer used by the S3 client".
 
+validators(s3_uploader) ->
+    [fun validate_part_size/1].
+
+validate_part_size(Conf) ->
+    Min = hocon_maps:get(<<"min_part_size">>, Conf),
+    Max = hocon_maps:get(<<"max_part_size">>, Conf),
+    Min =< Max orelse {error, <<"Inconsistent 'min_part_size': cannot exceed 'max_part_size'">>}.
+
 translate(Conf) ->
     translate(Conf, #{}).