The passive solar house in Beijing area where solar energy resource is abundant in winter was taken to study.The properties such as long-time sunshine and intense solar radiation.Based on building thermal physics,heat transfer and phase change storage theories,the feasibility and energy conservation characteristic of the composite phase change material(PCM) wallboard in the passive solar house were studied by the methods of computer simulation and experimental analysis were studied,which provides useful reference for the application of heat storing technology of the PCM and the utilization of renewable energy in the building energy conservation.