In inter-provincial power trading, the collaborative clearing of capacity market and electricity market needs to simultaneously deal with strategic bidding interaction, transmission coupling and high-dimensional operational constraints. Based on two-layer market interaction and mixed-integer optimization architecture, a cooperative clearing model based on game equilibrium is established. The upper layer is the strategic offer of the provincial seller and buyer in the capacity market and the electricity market, and the lower layer is the joint clearing under tie-line restrictions, reserve requirements, hill climbing boundaries and node balance constraints. Combining KKT reconstruction, binary linearization, and branch-and-cut acceleration, the equalization process is transformed into a solvable mixed-integer framework. The experimental results on a 12-province system containing 168 generating units, 36 inter-provincial channels and 24 periods show that under different load scenarios, the proposed method reduces the total power purchase cost by 11.8%, reduces the new energy power abandonment rate by 14.6%, improves the clearing convergence efficiency by 23.4%, and keeps the equilibrium deviation within 3.1%.
