<p>Acquiring geological information on rock mass structure is fundamental for rock mass quality grading and homogenization zoning. Laser point cloud and close-range photogrammetry technology provide the conditions for the digital measurement of geological information of rock mass structure. Traditional methods based on point cloud segmentation algorithms for extracting structural planes can only be applied to relatively regular rock mass structures. When encountering complex geological and engineering conditions, blasting excavation faces are often misjudged as rock mass structural planes, and the automation measurement of other geological information elements besides the orientation of structural planes is not yet perfect. This study proposes a digital automatic extraction method for rock mass structural planes based on the ISODATA clustering algorithm, which is based on the mathematical representation of geometric features such as structural planes in the same direction and plane. Furthermore, a digital measurement method for attitude, trajectory, and spacing is proposed based on point cloud data features. The digital automatic measurement of rock mass structural geological information is achieved with ArcGIS data processing tools. Finally, the reliability and efficiency of the method proposed in this paper were verified by combining the geological logging work of the underground excavation of the large-span station tunnel face at Dan Shan Station on Qingdao Metro Line 15.</p>