Abstract: The power system is undergoing a transformation towards cleanliness and low carbonization. The flexible regulation role of energy storage is becoming increasingly prominent. However, the mode of energy storage participating in market transactions and the optimization of its revenue still face challenges. Taking the Jiangsu electricity spot market as an example, this paper, aiming at the special mechanism where energy storage participates in market clearing but does not participate in pricing, constructs a mixed-integer linear programming model that incorporates the physical constraints of energy storage and market rules. Starting from the mathematical model of the day-ahead market clearing, it analyzes the internal relationship between the energy storage bidding strategy and the clearing results. The research shows that: When the price spread of energy storage charging and discharging remains unchanged, the day-ahead clearing volume remains unchanged. Reducing the price spread of charging and discharging can significantly increase the clearing volume of energy storage. The day-ahead clearing volume of energy storage and the price spread of charging and discharging show a monotonically non-increasing relationship. The conclusions drawn provide a theoretical basis and practical reference for the bidding optimization of energy storage participating in the spot market and the design of relevant mechanisms.