Abstract: Automatic identification of the intersections of trunks and branches is necessary in processing standing tree pruning by robot.Calculation for the relative space position of the intersections is also necessary.This paper presents a new method to identify the intersections of trunks and branches that can be used in standing tree pruning robot.The method includes four steps:1) transforming the gray image into the binary image using the mathematical morphological method;2) getting the skeleton of the trunks in the binary image via the mathematical morphological method;3) calculating the convolution integration between the skeleton of the trunks and a template that is a 3×3 matrix,whose elements are all one;4) comparing the result of the convolution integration with the given threshold,which is 3 in this paper.If the result is more than the threshold,the pixel is an intersection.The experimental results demonstrate that the method is available for automatic identification of the intersections and for automatic calculation of the relative space position of the intersections.