The invention discloses an SM9 decryption method and device. The method comprises the steps that firstly, a decryption client side obtains a first zone sub-secret key M of an identification private key S_A corresponding to the identification of the decryption client side, wherein a second zone sub-secret key N of the identification private key S_A is obtained by a decryption server side corresponding to the decryption client side, a secret key generating center randomly selects a main secret key, and a system parameter set is generated; secondly, an encrypted message C and a partial data decryption secret key seed T_s of N are obtained from the decryption server side; thirdly, a partial data decryption secret key seed T_c is obtained from the encrypted message C and M to decode a secret key seed T_c, a complete decryption secret key seed T is recovered according to T_s and T_c, and T is used to carry out complete decryption on encrypted messages. In the decryption process, the first zone sub-secret key M and the second zone sub-secret key N need to be obtained, then M, N and the encrypted message C are used for recovering the decryption secret key seed T to carry out complete decryption, and the method is simple and safe.