Based on deformation compatibility principle of subgrade and pavement, combined with the pavement deflection control standard of current highway related code, the tolerance value of dynamic deformation of soft rock subgrade top is obtained. The theoretical solutions of elastic multilayered road structures under dynamic doublecircular loads are derived by using the transmissionreflection matrix method and the superposition principle. The dynamic deformation of soft rock subgrade top is deduced with inverse Hankel transformation. The critical value of resilient modulus of soft rock filled in area is determined based on the dynamic deformation control method. According to the thickness of the subgrade structure provided by the existing highway code,  control requirements of the resilient modulus of the soft rock filler satisfying the condition of dynamic deformation is put forward, and the soft rock filler is classified according to the resilient modulus. The results of this research can provide guidance for the optimization of the soft rock filler.