The invention relates to a liquid flow battery energy storage multi-stage comprehensive energy efficiency evaluation method, which comprises the following steps of establishing a liquid flow battery energy storage performance evaluation index and a benefit evaluation index; calculating the correlation coefficient matrix of the performance index, obtaining the weight and time weight of each performance index, and determining the comprehensive evaluation value of the performance evaluation index; based on the entropy method, obtaining the weight of each benefit index, and determining the comprehensive evaluation value of the benefit evaluation index; and finally, considering the bias of the evaluator to the performance and benefit, and obtaining the comprehensive energy efficiency evaluationindex value evaluation method considering the performance and economy. The invention comprehensively evaluates the operation effect of the liquid flow battery energy storage demonstration project from two angles of the performance and the benefit, and improves the reliability of the comprehensive energy efficiency evaluation.