Abstract: On the background of the construction of the new power system, frequent extreme weather, soaring primary energy prices, and the normalization of power supply emergency, this paper proposes a electricity spot market mechanism based on the marginal cost comparison bidding mode, which provides a feasible idea for coordinating the interests of multiple market players and coordinating inter-provincial and intra-provincial transactions. Firstly, the challenges faced by the existing electricity spot market mechanism in coordinating the interests of multiple market players are deeply analyzed. Based on the marginal cost comparison bidding mode, the cost characteristics of different types of generator units are deeply considered, and a two-stage electricity spot market mechanism for hierarchical marginal pricing is proposed, which can effectively coordinate the guidability of the cost of the power generation side, the affordability of the electricity fee of the power consumption side, and the incentive of the renewable energy units. Then, a two-stage inter-provincial intra-provincial spot market mechanism based on the marginal cost comparison bidding mode is proposed, and its application value is discussed. Finally, a case analysis is carried out based on the simulation platform of the electricity spot market, and the effectiveness and feasibility of the proposed market mechanism are verified.