The invention discloses a method and system for measuring the volume flow of a material on a conveying belt, which can measure the volume flow of a solid material having an irregular surface on the conveying belt. The measurement method includes: a, acquiring first position information of a plurality of points of a surface of thee conveying belt, wherein the plurality of points are positioned in the same section; b, acquiring second position information of a plurality of points of a material surface in each section of a plurality of sections of the material, wherein the plurality of points of the material surface in each section are corresponding to the plurality of points of the step a in a one-to-one manner; c, acquiring a distance between every two corresponding points in each section of the plurality of sections of the material according o the first position information and the second position information; d, drawing up a plurality of class trapezoids according to the distance between every two corresponding points, calculating the areas of the plurality of class trapezoids, and calculating the sum of the area of each section of the material; and e, calculating the volume flow of the material according to the area of each section and the speed of the conveying belt.