The material, method, results and discussion of the research on the injury threshold of rabbit, monkey, and human being retina irradiated by argon laser light are introduced in this paper. When exposure time is 0.1s, the retinal injury threshold (ED50) is 0.506 W/cm2 for rabbit, 0.834W/cm2 for monkey, and 1.757 W/cm2 for human being. When exposure time is 1s, the retinal injury threshold is 0.428 W/cm2for rabbit.