Abstract: This paper introduced the general situation of BeiDou navigation satellite system (BD) and the applications of existing railway satellite navigation, analyzed the impact of changes in the technical system of BeiDou-3 global satellite navigation system (abbreviated as BD-3) on the application of existing railway satellite navigation, and studied the applicability of existing railway satellite navigation equipment to the application of BD-3, proposed a plan for the transition of existing railway satellite navigation applications to BD-3 service, which provided ideas for solving the transition problem of existing railway satellite navigation applications.