Abstract: Trans-regional and cross-provincial spot trading of surplus renewable energy adopts market-oriented ways to effectively promote the accommodation of renewable energy. On the premise of ensuring clearing calculation efficiency, how to improve the adaptability and expansibility of the clearing model, and to consider more complex operation constraints for the grid in the transregional and cross-provincial spot clearing, have become the key issues for the further development of the inter-provincial spot market. In this paper, an optimal clearing model for trans-regional and cross-provincial spot trading of surplus renewable energy is proposed. Combined with the characteristics of AC/DC hybrid power grids with ultra-high voltage and the pricing mechanism of trans-regional and cross-provincial transmission, a trading network model based on power flows and trading flows is constructed,and a transmission cost calculation method considering the discount of network loss is proposed. In the bidding clearing, the safety constraints such as the available capacity of the transmission channel, the ramping capacity and the cross-sectional flow limit are considered, and the goal of maximizing social welfare is determined to build a optimization clearing model for trans-regional and cross-provincial spot. An example is given to compare the results of optimal clearing model and matched clearing model. The validity of the proposed optimal clearing model is verified, and the applicability of the built model is analyzed.