Abstract: In order to calculate the internal force of the self-anchored suspension bridge under live loads, a new computing model is established. The new model adopts the fundamental principle of substitutional beam method provided by Chinese famous professor Li Guohao, and accounts for the differences in configuration and loading between self-anchored suspension bridge and traditional suspension bridge. A formula is derived to calculate the horizontal component of the pulling force of the cable caused by live loads; thereby, the internal forces of the girder in self-anchored suspension bridge can be determined. The proposed method is illustrated with a bridge. Comparing with results from two-dimensional and three-dimensional FEM, the accuracy of this method is demonstrated to be reasonable. Therefore, the proposed method can be used in bridge design.