Responsivity is an important factor reflecting the performance of photoelectric detector,responsivity was reduced when the detector was damaged by laser.In this paper,the damage mechanism of detector under laser irradation was analyzed.The spetal responsivity of the detector irradiated by Nd∶YAG laser with different power density was measured.And the principle of responsivity of detector irradiated was investigated.The paper has some reference values for the research on electro-optical countermeasure and detector anti-damage for laser.