Abstract: An underground gas storage (USG) has two functions of seasonal peak shaving and strategic energy storage with gas wells acting as both injectors and producers. Compared with gas production process, high-pressure gas injection is more risky and there is no available performance evaluation method. Evaluation of gas injection performance is one of the core technology to guarantee the safe operation of USG and the evaluation accuracy will directly affect the capacity and peak shaving ability of gas storage. Based on the alternative injection-production operation law and by means of unsteady gas production analysis method, the paper presents a flow model suitable for gas injection of Hutubi USG, establishes 2 dimensionless gas-injection analysis charts and a dynamic matching method through a series of mathematical transformation, then puts parameters such as gas injection radius, skin factor and permeability etc. obtained from the unsteady gas injection analysis into the unsteady gas injection equation to realize full-cycle injection-production history matching for single wells, and finally performs well pressure prediction according to the actual situations of emergency peak shaving and surface facilities. The practice shows that the method could realize not only the quantitative evaluation of gas injection capacity of UGS, but also the accurate pressure prediction, which could provide the basis for optimization of gas injection allocation.