A capacity compensation pricing method for storage considering the capacity supporting contribution is proposed for the capacity cost recovery of storage in the spot market. First, on analyzing the equivalent capacity of storage when discharging during peak hours, this paper designs a capacity compensation mechanism based on capacity depreciation factor of storages of varied discharging duration. Then, the spot market model with storage is formulated to simulate operating status of storage as well as the equivalent capacity model of storage with stochastic market scenarios. The capacity depreciation factor and capacity price of storage of different duration can be derived from the loss of the load probability index, so that the capacity compensation of storage can reflect the effective capacity contribution to the system. Finally, the effectiveness of capacity compensation for storage of different duration is verified by a numerical case study.