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In traditional forest resources survey, it was hard to get tree structure parameters due to its different shapes and complex structures. Totally six stand trees were selected as a sample data in the campus of Beijing Forestry University. By using ground-based laser scanner as a tool to acquire single tree scanning point cloud data, the canopy gap fraction was calculated based on Lambert azimuthal equal area projection and stereographic projection;tree crown volume and surface area were extracted by two methods: irregular surface projection and voxel method by using cloud point data. The results showed that the average relative error of two methods for gap fraction was 0.03, and the extraction result using stereographic projection was smaller than that using Lambert azimuthal equal area projection;the relative error of crown volume of two kinds of extraction methods was 5.32%~12.43%, the average relative error was 9.29%, the relative error of the extracted crown surface area was 1.40%~5.21%, the average relative error was 3.33%. The difference between the results of the two methods were not very significant, therefore, the extraction of gap fraction, crown volume and surface area based on the use of the point cloud data can provide a more reliable data support for 3D green quantity, calculation of trees biomass, photosynthetic ability etc.