The invention discloses a method for secure communication of a wireless sensor network based on a combined password, belonging to the field of secret communication. The method comprises the following steps that a base station sets and exposes system parameters and respectively generates public and private key pairs (QU, SU) and (QI, SI) for a user U and a node I; when the user is communicated with the sensor node, the user utilizes SU and QI to carry out signature and encryption on K1 in sequence based on a preset session key K1, and then the user sends a ciphertext to a receiving end, and the receiving end utilizes SI and QU to carry out decryption and verification in sequence; and lastly, the user utilizes the session key K1 to realize secure communication. When the sensor node needs to be communicated with the user, the node still utilizes SI and QU to carry out signature and encryption on a selected session key K2 in sequence, and then the user sends the ciphertext to the receiving end, and the receiving end still utilizes SU and QI to carry out decryption and verification. According to the method, secure communication of the wireless sensor network is realized by utilizing a combined public key password, so that the storage requirements for identity information and the cost for the base station to produce a private key are greatly reduced.