Solar PV module with cool-storage mode, a new type of photovoltaic module integrated a cool storage tank was developed for improving the conversion efficiency of solar cell by engineering thermophysics ways. Outdoor experiments were done from Oct., 2007 to Nov., 2008, and the characteristics of temperature, power output and conversion efficiency of the PV modular were measured and analyzed. The results show that operating temperature of the solar PV module with cool-storage mode has been greatly reduced, and the effciency has a corresponding increases. Comparing with the flat solar PV module, the maximum temperature drop of solar PV module with cool-storage mode is up to 26.5°C, instantaneous power output raises 18% relatively as well as the daily power output increases more than 14%.