Using finite element analysis software ANSYS simulate the fully flexural experimental process of the concrete box girder,the analysis results agree well with the experimental results, which confirmed the feasibility that ANSYS was used to analyse such box girder.The parametric analysis was presented for the influencing factors of the box girder flexural performance, the influences on deflection of box girderstress, increment of CFRP were mainly analysed,a reliable theoretical analysis basis was provided for the engineering applica-tion of such box girder.