Abstract: In order to study the feasibility of BeiDou Navigation Satellite System (BDS)-3 Precise Point Positioning (PPP) in railway survey application, this paper used BDS-3 satellite observation data to deduce BDS-3 arbitrary dual-frequency undifferenced and uncombined PPP universal function model. By using this model, the paper carried out the PPP solutions and performance analysis of five dual-frequency combinations formed by BDS-3 satellite signals B1I, B3I, B1C and B2a, and used a railway observation data to calculate BDS-3 PPP. The results show that the number of visible satellites is about 7~11, and the spatial Position Dilution of Precision (PDOP) is about 2.0 during the observation period. The number of visible satellites is large and the spatial geometry distribution is good. BDS-3 can achieve centimeter-level positioning accuracy in both horizontal and elevation directions in static and pseudo-dynamic solution modes. This study can provide reference for the application of BDS-3 precision point positioning technology in railway survey.