The output characteristics of GaAs solar cells irradiated by a continuous semiconductor laser with a wavelength of 532 nm are investigated in this paper. The damage to GaAs solar cells under high power density laser is investigated via X-ray diffraction, photoluminescence, electroluminescence, and optical microscopy. The results show that when the laser power density of 0.06 W/cm², the conversion efficiency of the solar cell is the highest, which is 26%; after the cells are irradiated for 180 s by a laser with a power density of 15 W/cm², the performance of the cells began to decay, the diffraction intensity decreased, the full width at half maximum increased, and the crystal quality deteriorated. High power density laser irradiation can cause cracks on the surface of the GaAs solar cells, and the cracks emitted no light during the electroluminescence test. In addition, the fluorescence intensity in the irradiated area decreased significantly, and the luminescence peak is shifted to the right. The comprehensive characterization results show that high power density laser irradiation will degrade the crystal quality of GaAs solar cells and generate nonradiative recombination centers. These centers will generate internal defects in the material and lead to a reduction in the solar cell photoelectric conversion efficiency.