Abstract: The response of silicon p-n junction solar cell to DF laser irradiation is studied. It is found in the experiment that DF laser doesn't generate much photocarriers in the solar cell though the laser power is high enough to cause notable temperature rise. An approximate formula is deduced describing the temperature dependence of p-n junction leakage reverse current which is an important factor in the equation characterizing the output of the soar cell. With the equation, the photovoltaic effect and the temperature effect in the solar cell when laserirradiated are explained. Also with the formula, the output voltage of the solar cell under DF laser irradiation is calculated, which agrees with the experimental result．