The present invention relates to a method for checking connectivity between a BSC (Base Station Controller) and an MSC (Mobile Switching Center), including: the MSC loopbacking a circuit and sending a connectivity check command to the BSC to instruct the BSC to perform the connectivity check; the BSC performing the connectivity check according to the connectivity check command; if the connectivity check is successful, the BSC sends a Connectivity Check Success identifier to the MSC to instruct the MSC to cancel the self-loop of the circuit; if the connectivity check fails, the BSC sends a Clear Request message to the MSC to release the communication connection and cancel the self-loop of the circuit. Embodiments of the present invention implement quick and convenient locating of connection errors by adding a Connectivity Check command in the messages for A-interface.