The relay safety system provided by the present invention includes a relay, an emergency stop device, a trigger detection circuit, a sticking detection circuit, and a power-off circuit. The emergency stop device is used to generate an emergency stop signal. The trigger detection circuit connects the relay and the emergency stop device, and is used to convert the emergency stop signal into a trigger signal. The sticking detection circuit is connected to the trigger detection circuit and the relay, and is used to detect the sticking signal generated by the relay, and generate a power-off signal according to the trigger signal and the sticking signal. The power-off circuit is connected to the emergency stop device, the relay and the sticking detection circuit, and receives the power-off signal, and disconnects the power of the relay according to the power-off signal.