Driven by the "dual-carbon" goals, this study proposes a two-layer capacity optimization configuration method for compressed air energy storage in abandoned mines, addressing the challenges of new energy consumption and the resource utilization demand of abandoned mines. Unlike traditional static capacity determination based solely on mine roadway space, this research balances economy and new energy consumption, providing a solution for energy storage system planning in abandoned mines. The proposed two-layer optimization model consists of a planning layer and an operation layer. The planning layer aims for comprehensive economic optimality, while the operation layer focuses on maximizing the system’s new energy consumption rate. These two layers interact iteratively, and the model is solved using an improved particle swarm optimization algorithm to obtain the optimal configuration scheme. Multi-scenario simulations based on the improved IEEE 33-node system show that, compared with the traditional fixed capacity configuration, the proposed model increases the new energy absorption rate by an average of 6.53% and reduces the total cost by 45.45% in four typical scenarios, verifying the effectiveness of the model in improving the new energy absorption capacity and economy.