For a groundwater source heat pump (GWHP) system, how to realize system high efficiency operation is very important issue. On basis of development idea of modular and open energy management, a model of non-energy-saving (NES) fault diagnosis has been presented, the model involves input of basic characteristic data and index characteristic data and output of NES fault factors, the relationship database between input and output can be established by using related special knowledge and experts experiences, the weigh values and threshold values to connect the complex non linear mapping relationship of input and output can be obtained based on artificial neural network back propagation algorithm, then a NES fault diagnosis software of GWHP system operation can be developed. According to the requirements of monitoring data of the software, various sensors and a data acquisition device etc. are selected, finally the hardware system combined with a NES fault diagnosis software can be generated and become a effective part of total energy management information platform.