The low-angle and dark-field lighting system is set up with common array LED source for the strip-surface scratch defects. Meanwhile, illumination function in the given area is derived on the basis of LED lighting system, which receives the light intensity distribution function of LED by the curve fitting. The lighting system model is built based on the distribution function. and the Tracepro is used to simulate the lighting system model, and the relation is analyzed between the parameter β，S and illumination uniformity ΔE, which provides the corresponding basis for setting up the lighting system of visual inspection. Finally, the simulation results are verified through lighting experiments.