Bamboo resources have efficient carbon-sequestration capabilities, and their economic contributions to global carbon balance and carbon trading have attracted widespread attention. However, because of the complexity and the high canopy density of bamboo canopy structure, traditional measurement methods cannot be used to precisely measure the accumulation amount. Therefore, LiDAR point cloud data of Phyllostachys pubescens canopy are obtained using three-dimensional laser scanner to estimate the accumulation amount by the point cloud density. Experimental results show that a mathematical relation exists between the accumulation amount of the bamboo canopy and the point cloud density of bamboo poles and branches. In a sample test, the model accuracy of the accumulation amount of the bamboo pole and branches in the canopy reached 95.53% and 91.36%, respectively.