The invention discloses a key heterogeneous defense method. According to the technical scheme adopted by the invention, the method comprises the steps of initiating a service request by a user on a user side according to the needs of the user; after receiving the user service request information, applying to a buffer pool for encryption by a forwarding control terminal; returning two encryption modes to a distributor and synchronizing a decryption mode of one of the encryption modes to executive bodies which receive the information by the buffer pool; transmitting the information encrypted byadopting the encryption mode provided with the decryption mode and the other encryption mode to the executive bodies by the distributor and repeating the method to generate 2n encryption and decryption modes, where the n is the number of executive bodies; after receiving the encrypted information, decrypting the information to generate result information, encrypting the result information and returning to a voter by the executive bodies; and making a vote according to a voting algorithm and returning the result to the user by the voter. The method disclosed by the invention has the advantagesthat while attackers are confused, the executive body non-external attack abnormality caused by the delay of the executive body decryption mode after the encryption modes are transformed is solved atthe same time.