The disclosure discloses a key sharing method for a Machine Type Communication (MTC) server, wherein when establishing a safe connection and performs safe communications with a first MTC server via a Generic Bootstrapping Architecture (GBA) process, an MTC device may send a second MTC server a request message containing a bootstrapping identifier (B-TID) currently used by the MTC device and the first MTC server and a host identifier NAF-ID 1 of the first MTC server; the second MTC server sends a Bootstrapping Server Function (BSF) an authentication request containing a host identifier NAF-ID 2 of the second MTC server, the B-TID, and NAF-ID; after verifying the validity of NAF-ID 2 and NAF-ID 1 , the BSF generates a session key K NAF according to the B-TID and the NAF-ID 1 , and sends the generated K NAF to the second MTC server. Accordingly, the disclosure further discloses a key sharing system for an MTC server. With the disclosure, the MTC device is enabled to perform safe communications simultaneously with a plurality of MTC servers, thereby enhancing the efficiency of network resources.