Building envelopes incorporating phase change materials (PCMs) can contribute to reducing the energy consumption of buildings and enhance indoor thermal environment comfort. In this study, two building models were developed in EnergyPlus to explore the applicability of using PCMs in different climate zones. Six significantly different cities from five climate zones in China have been investigated. The simulation results reflected that for climates with small fluctuation weather conditions, PCMs with appreciate transition temperature T-R can contribute to positive influences on energy saving. For example, in Guangzhou, PCMs with T-R of near 26(o)C and 22(o)C contribute to the highest energy-saving rates of 12.0% and 12.4%, for external and internal PCMs addition. And the ideal transition temperature for each climates is subjected to its own outdoor comprehensive temperatures and its indoor set temperature, for external and internal PCMs addition, respectively. For other climates with the big fluctuation weather condition, PCMs' latent heat function to the energy savings is not significant.