The invention provides a communication method, device and system based on a combined public key cryptography system. The method includes the steps of obtaining a private key of a first node from a secret key generating center through the first node, obtaining identification of a second node according to an adjacent node identification list, calculating a public key of the second node according to the identification of the second node, calculating a shared secret key parameter of the first node according to the secret key of the first node and the public key of the second node, then, calculating a shared secret key of the first node according to the shared secret key parameter of the first node, generating a first secret key verification code corresponding to the shared secret key of the first node, sending shared secret key verification information with the first secret key verification code to the second node, and receiving shared secret key response information from the second node. The calculation steps can be completed offline, the number of times of interaction between the nodes is lowered, and therefore when the first node starts verification, verification can be completed in a quite short period of time, and verification efficiency is improved.