Abstract: The perpetual laser damage effects of silicon PIN photoelectric diodes and silicon avalanche photodiodes irradiated by a laser of 1.06μm or 0.53μm wavelength are studied.The laser damage thresholds of the detectors are experimentally measured.The main reason of causing the perpetual damage are the laser heat singe on the PN connect of photoelectric diodes.The damage thresholds are relative to the laser wavelength,pulse width and the photodiod structure.