The invention discloses an electricity energy efficiency monitoring and evaluating system applied to an enterprise and an evaluating method thereof. The electricity energy efficiency monitoring and evaluating system applied to the enterprise comprises a signal acquisition layer, a wireless communication layer and a system base station layer, wherein the signal acquisition layer transmits signals to the system base station layer through the wireless communication layer, and then the electricity energy consumption condition of the enterprise can be detected in real time and can be analyzed and evaluated objectively and practically. The evaluating method of the electricity energy efficiency monitoring and evaluating system applied to the enterprise is based on the analytic hierarchy process, and the weight ratios of all elements are calculated by means of an objective weight assignment method. By the adoption of the electricity energy efficiency monitoring and evaluating system applied to the enterprise and the evaluating method thereof, the electricity energy efficiency of the enterprise can be monitored in real time, the load of the enterprise can be managed, the type unification management of index data can be conducted by comparing the electricity energy efficiency of the enterprise with the industrial standard regulated in China or the industrial advanced level, the electricity energy efficiency of the enterprise can be evaluated objectively, and objective colors and a huge amount of calculation can be reduced as far as possible.