Relying on the project Application and Demonstration of Smart Building Energy System Based on DC Microgrid Technology-of Shanghai Science and Technology Commission, the research about planning, application, maintenance and control of energy system on smart building were carried out. With the integration of multiple technologies which include solar photovoltaic, energy storage, low-voltage DC power and flexible electricity, a demonstration project based on PSDF (Photovoltaic, Storage, DC, Flexible) technology was built. The demonstration project constructed an energy system application scenario of multi-energy complementary and collaborative optimization, which achieved remarkable energysaving effect and can be replicated nationwide.