An implementing method for removing duplication protection for multimedia messaging service interworking forwarding message and multimedia messaging service interworking gateway. The method determines whether to return response message according to the different value of the acknowledgement request field of the request signaling. Using the SMTP-interactive-status code as a criterion, when the acknowledgement request field is set to be “NO”, requesting not to return the response message, and when the acknowledgement request field is set to be “YES”, requesting to return the response message. Determine whether the forwarding is successful by determining whether the SMTP-sending-status code returned by the response signaling is received according to the replying status of the response signaling.