In the field of forestry, the terrestrial 3D laser scanning (TLS) technology is used to obtain the measurement factors in survey, but not so often to measure the volume of shrubs. This paper discusses the TLS system components, the operating principle, based on the point cloud data of the amorpha, and the crown height and the crown diameter of 29 amorpha plants were measured. With the overall convex hull algorithm, the sliced convex hull algorithm, the slice segmentation algorithm and the three-dimensional grid algorithm, the canopy volume was determined, then the canopy volume, the crown height and the crown diameter were correlated, and thus the appropriate measurement method for the shrub volume was selected. The results show that the stereo grid algorithm is the best way to measure the canopy volume of plant, which has the same structural characteristics with amorpha, and can be used as the foundation for the TLS technology to monitor wild shrub growth conditions.