Abstract: The mathematical model of direct expansion solar assisted heat pump system based on photovoltaic/thermal（PV/T）panel has been constructed and the parameter analysis have been conducted. The PV is coupled with evaporator to form a direct-expansion PV/T module,which reduces the PV cells’ temperature and improves the overall efficiency while increasing the evaporating pressure and temperature. The system COP increases with the increase of PV/T area,solar radiation,and ambient temperature. The system COP can reach 5.79 when the solar radiation intensity is 600 W/m~2,and the electrical,thermal and overall efficiencies is 17.77%,55.76%and 75.49%,respectively. Moreover,the PV panel can meet the power demand of the system while providing 21.4% electricity to the power grid.