Abstract: Through analyzing sensitivity formula of laser triangulation measuring system, effect of optical structure parameters on system sensitivity is analyzed, which mainly include measured surface fluctuation, magnification of imaging system and working angle as well. Additionally, laser triangulation system of surface roughness is established, and influence of working angle on sensitivity is experimentally studied. Results show that larger working angle can achieve higher system sensitivity. However, when working angle is large, it needs to consider optical magnification and working angle on sensitivity of integrated influence and ensure that intensity of light receiver is greater than its sensitivity. For measuring system used in this paper, working angle corresponding to highest sensitivity equals to about 70°.