The energy consumption evaluation indexes of fan units and pipe network system are obtained by referring to national standards and setting up a subtarget set of energy consumption evaluation,AHP analytic hierarchy process was used to analyze and compare the factors affecting energy consumption, and EXCEL software was used to deal with them. The influence degree of each factor on energy consumption was obtained, namely the weight of each factor.Using fuzzy mathematics,combining with the weight of all the factors obtained,evaluate the energy consumption for fan unit and pipe network system.Verified by examples,the system is in excellent condition,and it is consistent with the actual situation.