The present invention relates to signaling control method for the peer-to-peer network caching service based on the IMS. The method comprises the following steps: a user requesting entity sends out a request of retrieving a target file to an index server, the index server retrieves one or a plurality of target user entities through internal retrieval algorithm, and returns the retrieval results to the requesting user entity by using the multi-option reorientation response message in the SIP protocol, the multi-option reorientation response message consists of the caching server information, the caching server information adopts a unified resource indicant of the caching server or the IP address of the caching server; the requesting user entity sends an invitation request message to the caching server, to establish the TCP data connection used for downloading the target file. The present invention adopts the request and response message of the SIP protocol standard, through adding a first domain and the message content, the IMS network is avoided from suffering the large-scale upgrading and reconstruction, and the flexible caching service is realized through the flexibility of the SIP protocol.