Abstract: A model was developed for a vibrating compactor system with slowly varying parameters of compacted material taken into account. The model was solved asymptotically by piecewise linearization with a numerical simulation done analytically. The YZC-1 vibrating compactor was tested in site and the results were compared with simulation results. It was shown that the model is developed properly and calculation results are basically accurate. In the compacting process the natural frequency of the lower part of compactor increases with increasing stiffness of the material to be compacted and increases gradually with decreasing damping. It is necessary to choose rationally the excitation frequency, since increasing the excitation frequency will cause shake that makes operators very uncomfortable though it can increase the exciting force to improve the compacting effect on road material. In addition, the chaotic motion is also able to improve compacting effect.