Abstract: The primary condition of rock slope stability analysis is the determination of the most dangerous sliding surface. In this paper, Dijkstra algorithm was utilized to search for the most dangerous sliding surface of the high rock slope of the urban flood control project in Yongji County, Jilin Province. The fracture system was identified and interpreted by the digital close-range photogrammetry method. Considering the complexity of the fracture system in the high rock slope, it is extremely difficult to search for the most dangerous sliding surface on the three-dimensional scale. Therefore, the representative slope of the study area was selected and the Dijkstra algorithm was used to search the most dangerous sliding surface in the two-dimensional section plane of high rock slope. The research results show that the connectivity rate of the potentially dangerous sliding surface of the main sliding surface ranges from 59.87% to 70.45%. The potentially dangerous sliding surface with the maximum connectivity rate of 70.45% is regarded as the potentially most dangerous sliding surface.