Abstract: Disclosed is a method of high-precision 3D reconstruction of existing railway track lines based on UAV multi-view images, including: acquiring initial data, acquiring a UAV image rail top centerline, calculating a rail top centerline based on a nonlinear least squares method, and calculating three-dimensional coordinates of the rail centerline. Based on the multi-view geometry principle in computer vision and photogrammetry, object space coordinates of the line can be directly calculated by using image information, which does not require outdoor workers to work online and can effectively improve the safety of railway operation line surveying and mapping. Therefore, this method has important engineering application value and application prospect.