Acceleration signals of mass and electrodynamics shaker were measured. Least-squares method was applied and the trend items of the signals generated by shaker were eliminated. The polynomial dynamic model of polyethylene was established. The stiffness and damping of a load condition was identified. Runge-Kutta method was applied to reconstruct force-displacement curve and the correctness of the model was proved. The parameters of other load conditions were obtained with the same method. The computed results can be references for vibration isolation packaging.