Effects of femtosecond laser irradiation on GaAs/Ge solar cells are studied. Optical microscope and noncontact optical profilometer are used to measure the surface morphology of the solar cells and the the volt-ampere characteristic test system is used to test the photovoltaic properties. The damage degree of ablation on the surface morphology and electrical properties is analysed. The results indicate that when the laser energy density is below 0.53 J/cm2, the damage only reaches the anti-reflection film. With the increase of laser energy density, the damage depth of the solar cell is increasing, when the laser energy density reaches 0.78 J/cm2, the damage gets to the emitter region. With the density increasing, the electric properties such as short circuit current, open circuit voltage, maximum power and filling factor suffer a certain degradation. The decay amplitude of the electric properties increase at first and then decrease. Among all the evaluated electric properties, maximum power degrades most remarkably. In conclusion, laser irradiation could induce a great damage in GaAs/Ge solar cells, which influences the electric properties directly.