The present invention discloses a method, a device, and a communications system for managing and querying mapping information. The method for managing mapping information includes: signing a mapping information pair by using a private key of a certificate corresponding to a prefix in the mapping information pair to generate a signed mapping pair; submitting the signed mapping pair to a registration agent (RA) in a transit network; and sharing, by the RA, the signed mapping pair with other RAs through data synchronization. With the mapping information management method, data transmission method, devices and communications system provided by the present invention, the security of mapping information in registration, query, and synchronization operations is guaranteed.