Abstract: Based on the principle of the minimum loss of prestress, by using finite element software the authors simulated the first loss of prestressed and the tensioning process in range of the stress and deformation of component. Meanwhile, they presented a method in simulating the frictional loss of prestress in the corrugated pipe duck, the loss of anchorage device deformation, the contraction of reinforcing steels and compress of juncture, the loss of concrete elastic compression in finite element software. By using ANSYS the authors simulated the tension sequence of the post-tensioned box girder, and gave the optimal prestressed tensioning sequence fitting for different construction technology according to the simulation results.