To enhance the technology for forestry investigation,our study focused on the application of small unmanned aerial vehicle (UAV) equipped with non-measuring camera in forestry investigation.In the study,we selected the Shisanling Forest Farm in Beijing as the study area to implement the test of airborne photographing.Moreover,intended for the characteristics of lens distortion in camera and large error of exterior orientation elements of the camera platform in UAV,we utilized a camera calibration algorithm and exterior orientation elements to inverse the accuracy exterior and interior orientation,and obtained the stereo images and orthophotos.In addition,the ground control points (GCPs) were used to carry on the geometric correction in the whole photo,and 3D measurement tools to measure the tree height in the three-dimensional area,and the GCPs to measure the area and perimeter of the mosaic area.Finally,the photo-measured results of tree height,area and perimeter were fitted to the field-measured results with empirical models,which also tested the photo-measured results.The results show that the small UAV equipped with non-measuring cameras can meet the accuracy requirements of the height,area and perimeter for the forestry surveying,if the device could be adjusted and calibrated properly.And it,therefore,has broad prospects of application in forest investigation.