Abstract: Objective The pipeline bridge structure is one of the main ways for long-distance oil and gas pipelines to cross complex terrain such as highways. The damage of the pipeline bridge structure will lead to pipeline suspension, deformation and even fracture. Accurately evaluating the mechanical state of the pipeline after the damage of the pipeline bridge is the key to determine the repair plan and avoid the expansion of losses. Methods Taking the collapse accident of a pipeline bridge as an example, the theoretical model of elastic constraint of suspended pipeline is established, and the theoretical solution is derived based on the deformation coordination relationship. The stress state of pipeline is analyzed by CAESAR II finite element analysis software and ultrasonic stress detection technology. The theoretical solution is compared with the numerical solution, the ultrasonic stress detection value and the field measured value to verify the rationality and engineering applicability of the theoretical model. Results After the collapse of the pipe bridge, the theoretical solution, numerical solution and field measured value of the vertical displacement of the suspended pipeline are 58.8cm, 58.6cm and 60cm respectively. The error between the theoretical solution and the numerical solution and the field measured value is within 3%. The error between the theoretical solution and the numerical solution of the stress in the middle and end of the pipeline is within 3%, and the error between the theoretical solution and the ultrasonic stress detection value is not more than 18%. Based on the theoretical solution, finite element simulation and field ultrasonic testing data, the strength of the suspended pipeline is checked. The maximum equivalent stresses are 149.1 MPa, 148.8 MPa and 158.3 MPa, respectively, which meet the requirements of the specification, and the safety margin of the pipeline stress is sufficient. Conclusion By comparing the theoretical solution with the numerical solution, the measured value and the ultrasonic stress detection value, the rationality and applicability of the elastic constraint theoretical model of the suspended pipeline after the collapse of the pipeline bridge are verified. The theoretical model can provide a reference for the rapid analysis of pipeline safety status and emergency repair decision-making under similar pipeline bridge collapse accidents.