Abstract: For a modern P.C. (prestressed concrete) continuous rigid frame bridge, its stress state is complicated, and affected by construction process. To simulate its structural behavior during construction process, degenerate solid elements were used and a three-dimensional model was set up. Taking prestressed reinforcement as a part of structure, the equivalent nodal load was obtained to calculate the effect of tensioning bars. A three-parameter viscoelasticity model was adopted to simulate the concrete creep. A processing method for internal stress of stage model was developed. A P.C. continuous rigid frame bridge was employed for the case study. The results show that the stresses and deflections of P.C. continuous rigid frame bridge under dead loads are closely related to construction process, and that the stresses and deflections obtained with commonly-used method which ignores the effect of construction process have large deviation.