The invention discloses a block chain distributed dynamic network key generation, encryption and decryption method, which comprises the following steps of: (1) generating and encrypting a key, initializing a network, and starting a key management protocol of a distributed dynamic self-organizing network; (2) after the key management protocol is started, counting the key encryption times, startingto accumulate the key generation and encryption times, updating a key encryption algorithm after the specified times are reached, and waiting for a new round of key generation and encryption operation; and (3) after the secret key is generated and encrypted, broadcasting a message generated by the secret key to the whole network for verification. In order to solve the problem that potential safetyhazards exist due to dynamic changes of a blockchain distributed network, a secret key management protocol is designed, generation and encryption of a secret key are managed, the efficiency of secretkey generation and encryption and decryption processes is guaranteed, an encryption method of an iterative encryption algorithm is designed for attackers to forcibly crack the secret key or launch replay attacks, secret key loss is reduced, and transaction information transmission safety is guaranteed.