Abstract: Based on the application of material sorting in the actual industrial field production line, a comprehensive experiment case for the digital image processing course is designed. In the comprehensive experiment case, a material recognition and sorting robot system and an interactive graphical user interface are constructed. Students use Python as the programming language and apply the principle of material recognition to add the business logic code in the interactive graphical interface according to the actual engineering requirements. Students complete functions in the order of “image input-image processing-result output” to realize material sorting. In the design of this comprehensive experiment, the muti-level teaching method is adopted, and the experiment is divided into three levels including cognitive experiment, verification experiment and innovation experiment. This comprehensive experiment is a useful supplement to the existing theory teaching and helps to achieve the teaching objectives of the course.