For the deficiencies of existing method for reflecting the mechanical behaviors of box girder cross-section, a new deck beam finite element analysis method is proposed. This method is based on the presupposition of Kirchhoff. According to the existing stiffness equations of box girder wing and web, a new displacement function for diaphragm plates of the box girder is proposed, which could result in higher precision of diaphragm plates influence on box girder despite the stress precision of itself not being improved. Thus a new deck beam finite element analysis method for linear box girder is f...