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The tree crown volume is one of the important parameters to estimate the biomass. In order to make an accurate measurement of the tree crown volume with nondestruction, this paper took 3D laser point cloud data, which were used as a data source, to calculate volumes of sample trees. The 3D laser point cloud data were randomly selected by six species, totally 30 trees. First of all, this paper extracted the point cloud data of tree crown volume from all points after matching, mosaic, denoising and compression etc. Secondly, it extracted the edge feature points from the tree crown through the programming algorithm. Finally, the crown volume was calculated by using the principle of irregular triangle net (TIN). In this paper, the edge feature points, extracted from the programming algorithm, can maintain the whole body of the crown. The algorithm can further remove the redundant data, shorten the construction time of TIN and improve the calculation efficiency. In addition, tree species also have certain representativeness. Because they included conifer and broadleaf trees, so the crowns not only have the crown body posture characteristic of conifers, but also have crown body posture characteristic of broadleaf trees. The results were as follows: the RMSE was 0.832, the average absolute error was 0.49, and the average relative error was 1.75%. Comparing with the artificial measurement results by selecting five sample trees randomly, the precision was relatively good. It can be seen that there are few gaps between the two results, of which the accuracy can meet the requirements of production.