In order to solve the problem of light scattering, reflection or transmission caused by surface defects of optical components, which affects the imaging quality of optical systems, a surface defect detection method for optical components based on multispectral technology is studied. Collect multispectral images of surface defects on optical components, Laplace pyramid transformation algorithm is used to fuse multispectral images of surface defects in optical components and frame difference method is used to subtract two multispectral images of optical components and obtain binary image features of surface defects of optical components. Mark the connected regions of the multispectral image fusion results of optical components, and use parameters such as the aspect ratio of the image connected regions to detect the types, quantities, and sizes of surface defects on optical components. The experimental results show that the method can effectively detect different types of surface defects such as pitting, scratches and broken points, and the detection accuracy of surface defects is the highest 98.15%.