With the large-scale application of battery energ y storage i n diverse power system scenarios，the matching of energy storage battery selection with scenario requirements becomes an important issue in power system energy storage planning.Therefore，an optimization selection and capacity configuration method for electrochemical energy storage batteries combining the entropy weight （EW） method and the analytic hierarchy process （AHP），named EW-AHP，was proposed.Firstly，the differentiated requirements of two typical scenarios，peak shaving and frequency regulation，for energy storage batteries were analyzed，and the selection evaluation system and hierarchical structure of the battery energy storage system were established.Secondly，the subjective and objective weights of each decision indicator were calculated based on AHP and EW，respectively，and they were fused to form comprehensive fixed weights.Thirdly，the division of frequency regulation and peak shaving scenarios was realized by calculating the average fluctuation of grid-connected power and the peak-valley difference rate of load，and the fixed weights formed by EW-AHP were modified based on the indicator correction coefficients under the corresponding scenarios.Fin ally，through case analysis，the influence of the energy storage configuration capacity interval on battery selection was discussed，and optimization selection under different application scenarios and specific configuration capacity intervals was realized.Furthermore，the evaluation results of the technique for order preference by similarity to ideal solution （TOPSIS） method under fixed weights were compared，which verifies that the proposed method can dynamically adjust the decision weights of key indicators according to scenario requirements and improve the accuracy and rationality of energy storage battery selection.