Abstract: To test the divergence angle of a glass bead Scotchlite retroreflector, after utilizing a CMOS high-speed camera to take photos of laser spots imaged on a piece of parchment paper reflected by the glass bead Scotchlite retroreflector, the images of laser spots were processed and the divergence angle was calculated according to a certain geometric proportion. The divergence range of the retroreflector was 0.907°~0.956°.Results show that the test method is reasonable and has certain practical value.