Abstract: In view of problem that existing coal quantity detection method with laser instrument does not propose a clear method for laser line extraction, a detection method of instantaneous coal quantity of belt conveyor based on laser scanning was proposed. Image of loose coal on belt conveyor is obtained by digital camera and laser instrument, and laser line profile is extracted by using characteristics of Ohta color space, then laser line thinning and connection processing based on index table are performed. According to offline acquired baseline and laser line acquired in real time, cross-sectional area of coal is calculated using trapezoidal area cumulative method, and instantaneous coal quantity of belt conveyor is obtained real-timely. Test results show that coal quantity detection result of the method matches actual coal quantity, and the method has high accuracy and good real-time performance.