With the development of building and mechanical and electrical equipment technology, it is necessary to propose energy-saving design standards that meet the specific conditions of building climate and energy conservation in Jiangsu Province. Based on the distribution of public building types in Jiangsu Province, the energy-saving design technical path of new public buildings is proposed. By improving the thermal performance of building exterior windows and transparent curtain walls, the relative energy-saving rate of building envelope is 0.99%. By optimizing the energy efficiency of heating and air conditioning system, the average relative energy-saving rate of heating and air conditioning system is 5.17%. By reducing the power density of the lighting system, the relative energy-saving rate of the lighting system is 26.76%. According to the proportion of energy consumption of building envelope, heating and air conditioning system and lighting system, the comprehensive relative energy-saving rate of the building body is 2.95%. Using 20% area of building roof to set up a photovoltaic system, the average relative energy-saving of public buildings is 1.22%. After optimization, the average comprehensive energy-saving rate of new public buildings in Jiangsu Province reaches 76.17%.