In vitro prestressing technology is one of the main branches of post-tensioning prestressing system. In this paper, a comparative study of strain test and finite element analysis of extracorporeal anchorage system, static load and fatigue test of assemblies, and test study of extracorporeal bending ropes are carried out. The engineering design and construction examples show that this technology can be applied in the strengthening of long-span bridges, roofs and existing structures.