Abstract:  Security inputoutput benefit of power supply enterprise is a complicated system with multiple input and output. It is necessary to analyze the efficiency of the security input output to develop improvement measures to improve the security investment management level. Seven input indexes and two output indexes are selected on the basis of the definition of power supply enterprise’s security investment and security benefit. Then, a model of power supply enterprise’s security input and output is established based on data envelopment analysis (DEA). The model is applied to a case study and found that some of the power supply enterprises have low efficiency in security inputoutput and they need to optimize the use of security investment. The result shows that the DEA method can evaluate the efficiency of security inputoutput for power supply enterprise and find the insufficiency in optimizing safety input costs.