Abstract: Driven by the goal of “carbon emission peak and carbon neutrality” and affected by the geographical distribution and randomness of renewable energy, the importance of mutual support between regional power and flexibility using cross-regional trading as a medium is highlighted. At present, China is in the critical stage of building a unified national electricity market system, and an effective market mechanism is needed to manage large-scale inter-provincial electricity spot trading. Based on the above background, an inter-provincial electricity spot trading approach which does not depend on cross-regional bidders is designed. First, a market clearing model based on bidding zones is proposed and the zonal marginal pricing method is used to calculate the settlement price for each zone. Then, transmission tariffs for each transaction between regions are calculated according to power flow contributions based on the equivalent bilateral matching method. Finally, numerical examples verify the effectiveness of the proposed method. Compared with existing methods, the proposed method accomplishes inter-provincial electricity trading without relying on cross-regional bidders. It utilizes the capacity of transmission lines efficiently and protects the privacy of internal network information in each area during the market clearing process.