The invention discloses a method, a device and a system for traffic monitoring and switching, relates to the network security field, and aims to monitor malfunction of circuit protective equipment and switch traffic when the circuit protective equipment malfunctions. The method includes receiving data traffic sent by a sending device through a light path protective device; monitoring an average traffic value at the traffic output end of the circuit protective equipment; comparing the average traffic value with a threshold value; switching the data traffic to the light path protective device, and send the data traffic directly to a receiving device through the light path protective device when the average traffic value is smaller than the threshold value. The method, the device and the system for the traffic monitoring and switching is mainly applied to the network security field.