The Tianshui-Longnan Railway serves as an important project for guaranteeing Gansu Province’s development strategy of “consolidating the east, focusing on the west, deepening the south, and promoting the northward expansion”. This railway crosses the Qinling Mountains twice and passes through three distinct geomorphic units including the loess ridge, knoll, and gully areas, the moderately high mountainous area of the Tianshui-Xili basin, and the moderately high mountainous area of the Qinling Mountains from north to south. The complex geological tectonic setting and the intensive regional Cenozoic tectonic movements lead to environmental geological problems, such as large-scale landslide groups, Holocene active faults, and karst collapse along the railway line, which severely restrain the early-stage design of the line scheme and affect the safety and stability of the later construction and operation of the railway. By fully utilizing surveyed aerial remote sensing data, this study interpreted and analyzed various geological problems along the whole railway in detail according to high-precision stereo images and orthophoto images of realistic scenes. Moreover, this study assessed the scope, scale, stability, and possible impacts of the various geological problems on the line scheme by combining the data from field surveys. The results of this study will provide strong technical support for both the line scheme design and the field geological surveys of the Tianshui-Longnan Railway.