A method and a system for recognizing power consumption behaviors of electric appliances in a loop are provided. When a variation value of a power consumption information of the loop exceeds a threshold, a current value of the power consumption information is served as a main loop factor value of the loop, and a similar combinative factor value close to the main loop factor value is looked up in a behavior-factor mapping table. If the similar combinative factor value is not found, the main loop factor value corresponding to a new power consumption behavior is obtained according to the variation value of the power consumption information to reconstruct the behavior-factor mapping table. After obtaining the similar combinative factor value from the behavior-factor mapping table, a current electric appliance power consumption behavior of the loop is determined according to a power consumption behavior combination corresponding to the similar combinative factor value.