Directing against the energy consumption analysis and energy saving reconstruction of new wall of prefabricated single building in heating season, proposing a new type of assembled building structure system, with emphasis on new wall and concrete wall, taking the engineering construction of prefabricated single building in Chongqing as an example, the difference of energy consumption between the new wall of prefabricated single building and concrete wall have been compared and analyzed based on the simulation software DeST developed by Tsinghua University. The experiment result shows that the annual energy consumption of new wall in prefabricated single building model is lower than that of the concrete model compared with ordinary aluminum alloy single glass windows and energy-saving Windows. What’s more, the energy-saving rate of new wall can reach 29%, which equals 7500kwh of power or 923kg of standard coal. The average room temperature of prefabricated single building can reach 13.51°C compared with concrete model which average room temperature is 11.96°C. The difference of dynamic temperature between the two models can reach 2°C–4°C. Furthermore, the thermal load of the new wall model of the prefabricated single building is about 33.18 W/m 2 , the concrete model is about 63.1 W/m 2 . After the energy-saving reconstruction, the energy consumption of ordinary window system is 1200kwh/m 2 , the inert gas-plated low-e membrane hollow window system of that is 900kwh/m 2 and the saving energy rate is about 25%.