Abstract: Based on the important role of energy storage in regulating the randomness and volatility of new energy output, this paper proposes a rapid selection and configuration method of energy storage for new energy fluctuation mitigation, aiming at the difficulty of energy storage selection and configuration caused by the diversity of energy storage types and the complexity of parameters. Firstly, starting from the essence of the physical energy storage model, considering the multi-type parameters of energy storage, a multi-parameter equivalent conversion method of energy storage is proposed. In this method, the comparison of multi-parameters such as SOC, life, efficiency, and initial investment cost of energy storage is equivalent to the comparison of configuration cost of power and capacity, and the complex parameter relationship is comprehensively quantified and characterized to realize the rapid and accurate evaluation of energy storage value. Then, to ensure the smoothness of new energy output, the indicators of new energy fluctuation flattening under different time scales are established, and an optimal allocation model of energy storage with flat fluctuation of new energy is proposed. The model aims to minimize the cost of energy storage, the cost of power curtailment loss, and the penalty cost of new energy fluctuation exceeding the limit and considers the system's operating and energy storage constraints to optimize the technical and economic performance. Finally, according to the fluctuation flattening demand of an actual example, a variety of widely used energy storage systems are investigated. Different energy storage's technical and economic parameters are analyzed and compared based on the proposed multi-parameter equivalent conversion method of energy storage. The effectiveness and applicability of the proposed energy storage selection and configuration method and the new energy fluctuation flattening model are verified.