The invention discloses a method and system for keeping the functional consistency of an SOA service conversion language. The method comprises the steps that 1, new and old language services are deployed to the same production environment, and old language service receives a service request message of a client; 2, the old language service sends the service request message to the new language service according to the first preset proportion; 3, the new and old language services respond to the same service request message separately and generate the corresponding service response messages, and the same service request message and the corresponding service response messages are recorded; 4, whether or not the same service request message is matched with the corresponding service response messages in the step 3 is judged, if not, a new language service is optimized, and then the step 1 is executed again; 5, the new language service is online, and the service request messages of a client are received and processed. Accordingly, the service response difference can be positioned rapidly, manual testing can be greatly reduced, the system framework reconstruction correctness is guaranteed, and it is guaranteed that the new language service is put on production rapidly.