In this study, a phase change thermal storage plate, heated by hot air, was designed. It could be mounted on the internal wall of the building and applied in the building heating system. The thermal characteristics of the model room assisted by the phase change thermal storage system was experimentally studied and compared with that of ordinary room. The TRNSYS model of the phase change thermal storage building was employed to simulate the transient thermal characteristics. The measured and simulated results show that the temperature of the room assisted by the thermal storage system increased from 4 ℃~5 ℃ compared with the ordinary room, suggesting that the proposed system can improve the thermal comfort of the room. In addition, the TRNSYS model of the phase change thermal storage building can precisely forecast the transient thermal characteristics.