The use of phase change materials (PCMs) integrated into building envelopes had attracted more and more attentions. The selection of the parameters of the PCM was important for the application of it. In this paper, the sensible heat capacity method was used to establish the heat transfer module of the PCM wall. External and inner surface heat fluxes were simulated by the module. Influence of the melting temperature and latent heat to the thermal performance of the PCM was discussed. Results showed that the melting temperature should be close to the indoor air temperature to reduce the heat transferring to the room from the PCM wall and to improve the usage of the PCM. The latent heat of the PCM had no significant influence to the heat flux of the inner surface, but took large effect to the phase change time. This paper aimed to give theoretical support to the application of the PCM wall.