Abstract: In view of problems of false alarming and triboelectrification existed in existing coal conveying belt system with coal piling sensor to detect state of coal piling of belt, a non-contact detection method of coal piling of belt based on vision measurement was proposed. The method uses monocular vision technology in visual inspection to construct small hole imaging model, and can measure coal piling of belt. The experimental results show that the method has advantages of high real-time property and good detection effect with detection accuracy of about 95%, which complies with design requirements.