Heat transfer through the envelopment is critical for the selection of the capacity of the air condition equipment and control of building energy consumption. In this paper, quasi-steady state method is used for solving the heat transfer process of the phase change material (PCM) wall under cyclical climatic condition. Heat flux and total heat transfer during the phase change process are chosen to evaluate the thermal performance of the PCM wall. The heat flux is important for the selection of the capacity of the air condition equipment, and total heat transfer through the wall is important for the energy consumption of the air condition system. The influence of phase change temperature, latent heat and thermal conductivity to the heat flux and total heat transfer are all studied. Results show that: 1) when the phase change temperature is close to indoor air temperature, the heat flux and total heat transfer will be small; 2) with the increasing of the latent heat of the PCM, the heat flux decreases, but latent heat seems have litter influence to the energy saving of the PCM wall as comparing to wall without PCM; 3) With the increasing of the thermal conductivity of the PCM, the heat flux increases and the energy saving of the PCM wall as comparing to wall without PCM increases.