Abstract: The computing method for analyzing variable section member shape constants is realized in this paper.The stillness matrix of variable section structure about the independent model displcement is found by using the finite element pretreatment method with the fixed position vectors.The laterial stiffness matrix about the horizontal dynamic freedom degrees of the concentrated mass can be also found by static condensation method.Thus the earthquake resistance dynamic analysis and combination computation of vibration mold can be fulfilled by the Stodola teration method and the code earthquake response spectrum.