In order to evaluate the structural performance of stone arch bridges built in the Ming Dynasty and to suggest appropriate strengthening techniques, we studied Yongchang Bridge, an example of typical Ming stone arch bridges. First, the bridge was surveyed in detail to obtain its geometrical dimensions. Next, the architectural forms, configurations and damage were studied to provide bases for analysis. Then, the software of ANSYS was used to establish a finite element model of this bridge, to study the influence of loading, importance of structural elements and crack distribution. Finally, based on the analysis of actual status and structural performance, we proposed and compared two strengthening methods—the concrete strengthening method and the carbon fibre reinforced polymer (CFRP) strengthening method for the stone arch of this bridge in order to obtain an adaptive strengthening method for Yongchang Bridge. These results could be referred to in efforts to conserve similar ancient stone arch bridges.