For making the theoretic results close to the fact,two methods used to calculate the internal force of beams with finite length bearing several point loads and on soil foundation were compared.These two methods were based on the Winkler's assumption and the half-space elastic foundation theory respectively.Through theoretic analysis,the difference between the two methods was found.And with the aid of FLAC~(3D) analysis,it was clear that the results deduced by the method based on the Winkler's assumption were more close to the fact.