Structural health monitoring is an effective means to ensure the safe operation and maintenance of bridges and optimize the life cycle cost of bridges. Persistent Scatterer Interferometric Synthetic Aperture Radar （PS-InSAR） technology based on spaceborne synthetic aperture radar can realize long-term structural health monitoring of bridges with low cost， light weight and sustainability. In this paper， a high-speed railway steel arch bridge in China is taken as the research object， and 59 C-band Sentinel-1 radar satellite images from 2017 to 2018 are selected. The PS-InSAR technology is used to process the images to obtain the line of sight （LOS） displacement of the bridge， and the longitudinal displacement of the bearing is calculated according to the spatial geometric relationship of SAR imaging. The results show that the spatial and temporal characteristics of the longitudinal displacement of the bearing are consistent with the actual bridge structure， which verifies the feasibility of PS-InSAR technology to observe the displacement of the bridge structure. A linear correlation model between the longitudinal displacement of the bearing and the temperature is established and compared with the measured results of the structural health monitoring system. The two are in good agreement， and the relative error is close to 10 %， which verifies the reliability of PS-InSAR measurement of the bridge structure displacement. The displacement of the bridge bearing under the action of temperature is simulated by finite element method， and compared with the PS-InSAR displacement time series. The two trends are basically the same， and the LOS displacement error is within ［-10，10］ mm， which verifies the accuracy of PS-InSAR measurement of bridge structure displacement.