The complex processing of static-dynamic boundary switch is a significant step in the static-dynamic coupling simulation. To study the rationality of the traditional scheme for switching static-dynamic boundary condition types （from static boundary to viscous-spring boundary） and the applicability of the verification method, the works conducted are as followed: based on the superposition principle, a method for verifying the rationality of static-dynamic boundary switch is given （reference method）. Using the finite element method software ABAQUS and the self-developed VBEA2.0 program, which can automatically set viscous-spring boundary and seismic wave input, the dynamic earthquake response of layered free field and soil-underground structure models considering integral static-dynamic analysis is analyzed. Based on these results, the applicability of the reference method is discussed. Based on this reference method, a free field model with a typical unreasonable static-dynamic switch method is analyzed. The results illustrate that the reference method is suitable for both the layered free field model and the soil-underground structure model. The mechanism of the oscillated response in this procedure of static-dynamic boundary switch is generally caused by the non-static equilibrium of the static-dynamic coupling calculation model. Reasonable application of nodal reaction force, gravity and element stress is the key factor that affects the rationality of static-dynamic boundary switch.