The invention discloses a secure communication method and a secure communication system of a self-service device, and the self-service device, wherein the method comprises the following steps: a step1, a security module and a trusted end perform interactive identity authentication through issuing certificates and verifying signatures, and after passing identify authentication, the security moduleobtains an encryption secret key and a MAC secret key from the trusted end; a step 2, when the security module receives a service instruction, the security module identifies whether the service instruction is a preset critical service instruction, if so, the security module extracts sensitive data in the service instruction, and performs encryption treatment and security verification through theencryption secret key and the MAC secret key; a step 3, if the security verification in the step 2 is passed, the security module sends the service instruction to a matched critical service module. According to the invention, by the method, security services are provided for the critical service module on the self-service device, and security level of the self-service device is improved.