On the basis of the time-domain wave method coupled with the explicit finite element method for the viscous-spring artificial boundary issue, a simplified seismic wave input method for near-field wave analysis is proposed. In the present approach, the near-field model is stratified in the height direction, and then the seismic motion is converted to stress applied to the viscous-spring artificial boundary. Compared with the equivalent node force input method, the new method simplifies the antecedent work with acceptable accuracy. The numerical results obtained from free ground model indicate that: When the stratified size equals to the maximum size of the element mesh in dynamical analysis, the accuracy of the simplified model is totally same with that of the equivalent node method; when meshing the focus parts of the near-field model with the maximum size of dynamical analysis and meshing other parts with lager size, the dynamic response of caring part is still satisfied. Moreover, the dynamic response of a rock tunnel also demonstrates the effectiveness of the present simplified approach.