In order to study the operational safety status and structural bearing capacity of a stone masonry arch bridge in service on highways,a stone arch bridge that has been built for more than 30 years was measured in size and inspected for defects and appearance. The technical condition of the stone arch bridge was evaluated using a layered comprehensive evaluation method. The strength parameters of the material were estimated by strength testing based on on-site materials,and a Midas Civil finite element model was established to analyze the bearing capacity of the stone arch bridge under two new and old vehicle load standards:Auto -20,Trailer -100 (JTJ 021-89),and Highway -Ⅰ (JTG D60-2015). The results show that:1)The technical condition of the stone arch bridge in this project was evaluated as Class 2 according to the layered comprehensive evaluation method,with slight structural defects and no impact on its functional use;2) According to the finite element analysis results,the bearing capacity of the main arch crown,1/4 span,and arch foot section of the main arch ring all meet the requirements of load levels of Car -20,Trailer -100,and Highway -Ⅰ. The research methods and results of this article can provide some reference for similar projects.