As the first regional electricity spot market, the rational use of electricity market clearing algorithm is of great significance for the electricity trading in southern China region electricity market. Therefore, the clearing price calculation system and calculation algorithm of electricity spot market are studied, and a electricity spot market clearing algorithm considering inter-provincial transmission is proposed. Taking the social welfare maximization as the goal function, a market clearing mathematical model is established considering the impact of inter-provincial transmission and distribution price on the optimal allocation of power generation resources in the five provinces. Based on the transmission and distribution price of inter-provincial transmission components, the power generation plan and inter-provincial transmission components within the region are determined in a unified manner. Finally based on the application example of IEEE 9-bus system, the results show that the clearing method proposed in this paper can meet the requirements of continuous production of power system.