Energy storage system is of great significance for improving power quality, providing bridge power and energy management. Optimizing energy storage capacity configuration can improve the reliability and economy of system operation, which are important means. Considering the infrastructure and operation maintenance of photovoltaic building integration, this paper proposes a storage optimization method of photovoltaic building integration based on the improved CDKF(Central Difference Kalman Filter, CDKF) method, aiming at reducing the operating cost of the system and improving the economy. The introduction of the improved CDKF method can more accurately estimate the SOC of lithium battery, so as to improve the service life of battery pack. Taking an industrial park in China as the research case, it is solved by combining MATLAB with CPLEX. The results show that the effectiveness of the proposed optimization model.