In this study, a phase change thermal storage plate was proposed, which was placed in the inner side of the wall to construct hot air assisted phase change thermal storage system. A demonstration room was built in Chongqing to measure the transient thermal characteristics of the phase change thermal storage system, which were compared with that of ordinary room. The TRNSYS model of the phase change thermal storage building was presented to simulate the transient thermal characteristics. The measured and simulated results indicate that, the thermal storage system can observably increases the indoor temperature, thus improve the thermal comfortableness. On the other hand, the TRNSYS model of the phase change thermal storage building can precisely forecast the transient thermal characteristics.