When measuring the surface roughness of optical components, the measurement results are often one- sided. Therefore, a surface roughness measurement system for optical components based on image preprocessing tech- nology is designed. Obtain the interference image of the original component surface roughness, apply image denoising and tilt correction to the surface morphology image to obtain the filtering result, and implement image denoising through the adaptive median filtering algorithm. In the roughness parameter evaluation module, the evaluation length is defined based on the sampling length, and a comprehensive evaluation of the surface roughness of optical components is imple- mented. Measure the surface roughness of three optical components using a design system. The experimental results show that by designing the system, high imaging quality surface roughness interference images can be obtained, and comprehensive measurement of surface roughness of various components can be achieved, which has certain application value.