Abstract Phase change materials (PCM) and cool materials used in construction field cannot only effectively reduce buildings energy consumption, but also improve indoor thermal comfort and mitigate the urban heat island (UHI) condition. A novel energy efficiency roof coupled with PCM and cool materials has been conducted a field test in Tianjin of China. A kind of PCM-eutectic mixture was prepared, which was encapsulated in the polyethylene of raised temperature resistance (PE-RT) pipe, for using in building roofs. Thermal performances such as the roof surface temperatures and heat fluxes have been studied. The results indicated that, compared with reference rooms, the novel energy efficiency roof has shown good effect on decreasing the peaks of temperature and heat flux, which means that the influence of the outdoor circumstance on indoor environment has been weakened. In conclusion, it has been proved that the novel roof has good thermal insulation effect and energy efficiency potential.