Abstract: There are three kinds of methods for modeling and analyzing the existing curved girder bridges. They are single-beam method, grillage method and entity method. According to the previous literature, the single-beam method is not so accurate, but it is generally popular because of its higher speed in analyzing and higher efficiency in calculating. So the research of the single-beam method has practical significance. Central angle is the key factor to determine whether the curved girder bridge can be analyzed with the single-beam method. According to A ramp bridge of Jingkai overpass, several models of curved girder bridges with different spans, deck widths and central angles are built and compared using the grillage method and the single-beam method in this paper. Then by taking 10% as the control index, the applicable condition of the single-beam method is obtained.