Abstract: The carbon capture power plant(CCPP) is promising to promote renewable energy integration and low carbon transition, which can reduce the carbon emission and improve the power system flexibility. Based on the flexible operation of the CCPP, a joint grid-storage planning approach is proposed. In order to surmount the difficulty in calculating with massive scenarios, the improved k-means method is used to reduce the number of the scenarios of wind generation, and the typical scenarios can be determined according to the Spearman coefficient. The flexible operation mechanism of the CCPP is analyzed, and the model and quantitative indices of the power system flexibility are proposed. The bi-level model for the grid-storage planning considering the CCPP is built. The transmission line and energy storage system are configurated in the planning level, and the flexibility of the CCPP is considered in the operation level. The modified IEEE RTS-24 bus system is used to verify the proposed planning method, of which the results show superior performance in improving the flexibility margin of the power system and reducing the investment costs of the transmission line and energy storage system. The research results demonstrate the effectiveness of the proposed planning method.