Abstract: Building energy flexibility is significant in reducing the peak valley difference of air conditioning load. The phase change wall and precooling can effectively reduce the peak load by using precooling strategy but precooling may increase the total energy consumption. Therefore, it is necessary to comprehensively study and analyze its energy flexibility and energy consumption characteristics. In this study, taking the office building in Changsha in hot summer and cold winter as an example, the heat transfer model of the phase change wall is established and verified by comparison using the experimental data. On this basis, the flexibility potential of the phase change wall in summer under different precooling strategies is studied, and the sensitivity analysis of phase change parameters affecting flexibility is conducted. The results show that when the precooling temperature is 23 ℃, and the precooling duration is 4 h, the phase change wall can reduce the total cooling load during the peak period by 85.4%, while the total energy consumption is reduced by 2.6%. In addition, the phase change temperature of the phase change material has the most significant influence on flexibility, followed by position, density, phase change latent heat, thickness, phase change range. The thermal conductivity and specific capacity have little effect on flexibility. This study can provide a reference for the application of the phase change wall.