Aiming at the limitation that the existing inertial detection system based on single-axis fiber optic gyroscope cannot be used for deformation of horizontally curved bridge structure, a single-axis fiber optic gyroscope-based detection method for track deformation of curved bridges was proposed. Firstly, the principle of linear bridge deformation measuring based on single-axis fiber optic gyroscope was presented, and the error source of gyro and the difficulty of curved bridge detection were explained. Then the feasibility of curved track measuring by single-axis fiber optic gyroscope was analyzed according to the navigation algorithm. Secondly, a curved test track, a set of track detection trolley and wireless linear acquisition system were built. Finally, the integrated linear detection system on the test track was tested, different test stages by changing the deformation degree of the test track were performed, and then the actual measurement results were compared with the micrometer measurement results to verify the feasibility and accuracy of the proposed algorithm. The results show that the method can identify the precise deformation of curved track under different test stages with an accuracy of less than 1mm. Owing to the simple measuring principle, when the systematic implementation and low measuring cost combined with the equipment of bridge track detection, the proposed method will provide a new approach for the massive deformation measurement of various large-scale bridges without closing bridge or stopping bridge transportation.