Abstract: This paper reviews the basic content of key management，points out the limitation of the existing key agreement protocol.It introduces IBE public key cryptosystems in detail and homomorphic encryption scheme in the integer ring.The homomorphism key agreement based on IBE and homomorphic encryption scheme is presented.Compared with Diffie-Hellman protocol，its operation speed is more quickly；Compared with Key Agreement protocol based on password，it has better security.The protocol can use the public key of IBE to create the contributory，forward secrecy the session key.Finally，the security of the protocol is proved by BAN logic.