To meet the digital drilling and assembly need of large components in the cutting-edge manufacturing field, an automatic detection and positioning system for base hole are proposed by using the line laser scanner and the industrial robotic arm. Firstly, the hole bottom point cloud interpolation compensation is implemented for the three-dimensional point cloud of the base hole, and the rough edge feature point extraction of the base hole is achieved by using the bidirectional gradient constraint algorithm. Secondly, for extracting edge feature points, a refinement algorithm based on angle judgment and a compression algorithm based on plane fitting are used to achieve the refined extraction of edge feature points. Finally, the edge feature points are parameterized in the space circle, and the aperture and hole distance are obtained. The detection and positioning of the base hole are achieved. Experimental results show that the detection accuracy and positioning accuracy ( relative error) of the proposed method for the base hole are 1. 77% and 0. 24% , respectively. These values are better than the 2. 77% and 0. 46% of the traditional method. It can meet the digital drilling and assembly requirements of large parts in manufacturing.