The present invention provides a communication encryption method applied to the authentication of a service terminal to a client, wherein the client is connected with the service terminal. The communication encryption method comprises the following steps that S1 the client sends the information of a communication interface needing to communicate to the service terminal; S2 the service terminal encrypts the received information of the communication interface by a preset method, and returns the encrypted information of the communication interface to the client; S3 the client is communicated with the service terminal via the encrypted information of the communication interface, and the service terminal receives the encrypted information of the communication interface during the communication and then transforms the encrypted information into the information of the communication interface according to an inverse method of the preset method. The beneficial effects of the technical scheme are that: the communication between the client and the service terminal is safe, the verification speed is faster, and the defect in the prior art that the identity of the client needs to be verified every time, so that the performance of a server declines, is overcome.