A comprehensive power quality evaluation method based on the game theory and the improved technique for order performance by similarity to ideal solution (TOPSIS) is proposed to solve the problems caused by using a traditional and single evaluation method in the comprehensive evaluation of power quality, such as too strong subjective consciousness, incomplete evaluation of objective raw data and uneven weight distribution. Firstly, consider the actual engineering situation and establish the valuation index system, and the Best Worst Method (BWM) and criteria importance through intercriteria correlation (CRITIC) methods are used to obtain subjective weights and objective weights, respectively. Then, the game theory idea is introduced to combine the subjective and objective weights to avoid the defects of the single assignment method. Secondly, improve the fitting degree flaws of TOPSIS through relative distances, which makes it more applicable, and the evaluation objects are ranked in order of merit and gaven level determination by using the improved TOPSIS. Finally, the data collected from four monitoring points in a power supply area is used as an example to carry out a comprehensive evaluation of the power quality and a comparison with other evaluation methods. The results of the comparison analysis show that the relative distances of the improved TOPSIS method at monitoring points 2 and 3 are 0.232 and 0.256 respectively, which overcomes the shortcomings of the traditional method where the fit is similar and difficult to distinguish, indicating that the proposed method can reasonably evaluate and rank the power quality of monitoring points, verifying the effectiveness of the method.