The concept and method of external prestressing originated from France, but the early external prestressing system was not perfect, and there were defects in corrosion resistance, protection and structure. Therefore, the application of external prestressing in engineering can not show its superiority, which once made this technology stagnant. However, with the rapid development of unbonded prestressing and staying cables, the application of external prestressing system has brought vitality, especially in the last two decades, external prestressing system has been applied in a large number of projects abroad. The following are some representative projects in the development process of external prestressing system to illustrate, in order to have a further understanding of external prestressing.