According to the example of the combination of three corrugated steel webs(50m+80m+50m) across PC continuous box girder bridgewhich has been built and used.According to the bridge after the completion of operations, the Midas/Civil Software finite element modeling was used to make inspection and review of the bending and shear, crack deflection and strength three kinds of the most adverse effects (short-term effects of the combination, and the standard combination of values and ultimate limit state the basic combination).The results show that the structure can well meet the requirements specification and design documents when its finite element model is in condition of the three most adverse effects.