Abstract: In order to measure three-dimensional volume of trees with non-destruction and high accuracy, a digital elevation model was built in this paper through digital mapping software based on the trees point cloud data measured by three-dimensional laser scanning system. After building the triangulation, the volume of trees would be calculated through the earthwork calculation function of mapping software and the calculation principle of system was described in detail. 20 pines with different height and volume selected from experimental area were taken as research objects to measure with ten repeated tests by the proposed system, and then measured results were compared with manual measurement. It was concluded that experimental results had good agreement with manual measurement results (standard error was 3.54, absolute error was 7.002, relative error was 3.15%, and accuracy was up to 96.852%), so this system can be used in volume measurement of trees.