The invention discloses a heartbeat testing method, applied in a network device with service net mouth, comprising that: the network device periodically transmits heartbeat information to a testing opposite terminal through a heartbeat testing port, receives heartbeat response returned by the testing opposite terminal, selects a service net mouth free of service, when the heartbeat testing terminal does not receive the heartbeat response of the testing opposite terminal, transmits the heartbeat information to the testing opposite terminal through selected service net mouth; it is judged that, whether the selected service net mouth receives the heartbeat response of the testing opposite terminal, if true, determining the test opposite terminal is normal; otherwise, determining the testing opposite terminal. The invention also discloses a heartbeat testing device. According to the invention, judging correct degree of the tested state is advanced.