In order to accurately simulate the ultimate bearing capacity and crack state of prestressed concrete box girder under load, the plastic damage of the box girder is analysed by using nonlinear finite element method, and the simulation result is compared with the experimental data. The analysis result of plastic damage of concrete box girder shows that (1) it is feasible to introduce the damage factor into the nonlinear analysis of prestressed concrete box girder, and it can obtain the structural's bending shear resistance and failure characteristics accurately; ( 2 ) damage factor has great in...