Abstract: In the case of the second level aseismic requirement for regions of 8 seismicity, typical frames are designed according to Chinese design code of concrete structures. Varying moment amplification factors are used for floor columns. By means of nonlinear dynamic analytical program PL-AFJD, the responses of these frames under different earthquake excitations are obtained. The effect of the moment amplification factors on controlling plastic hinge mechanism under major earthquakes is studied, and the factors affecting the plastic hinge mechanism are identified. The results are helpful to optimal evaluation of the column moment amplification factors in Chinese concrete structure design code.