Abstract: This paper provides several typical mega plane frame designs on condition that the variables are the combination of varying amplification factors of moment at bottom sections of ground floor columns of the minor frame on the major beams. The elastoplastic dynamic analysis program Drain - 2d+ of the plane structure is used to get elastoplastic time- history analysis for each typical mega frame under the action of seism. After the analysis, the information of the mechanical transmutation characteristics, the emergency of the plastic hinge and the weak point of the whole structure under the action of seism is obtained, from which the correct thinking of how to obtain the design value of amplification factors of moments at bottom sections of ground floor columns of the minor frame on the major beams is found. The reasonable design values are recommended in this paper in order to provide some suggestions for the design of the reinforced concrete mega- frame structure.