Abstract: A method for automatic glass inspection on the production chain based on visual system was adopted. The method of illuminating is crucial to image in acquisition process,in order to avoid the illuminating jamming for judgment to guarantee the accurate identification result of different cracks by machine visual system, we carried out the research on the illuminating source system,including the luminous intensity,the wavelength and the position relative to line scan camera and glass which is on the production chain. We proposed a novel method of illuminating to achieve high quality image to solve problems caused by the influence of illuminating,with the analysis of influence between the defective part and the normal part when illuminating source system operates. It is proved that the method can realize realtime detecting to achieve accurate and reliable results,through a batch of glass samples tests. From the detection of glass image scanned under the condition provided by illuminating source system,the visual system can compute the defect and present the position size and depth,if the glass is not the acceptable product.