Abstract: In order to select the best design proposal in short time, the TOPSIS comprehensive evaluation method in the nuclear power plant DCS product design was introduced. It can intuitively show the different design proposals good or not good by data and shorten the time of the design proposal optimization. The design proposal selected by this method will be more reasonable and has good comprehensive performance indexes. The TOPSIS comprehensive evaluation method achieves good result in one of the nuclear power plant DCS cabinet design proposal optimization.