A chaotification method through attaching a vibro-impact subsystem was presented in order to obtain the low amplitude chaotic motion in vibration isolation system. The experimental setup was constructed and experiments were carried out. The results confirmed the effectiveness of this method based on the facts that the system may display chaotic motion obviously even when the amplitude of the isolated equipment is less than 0.2mm, and that not only the vibration transmitted to the base is decreased to some extent, but also the dominating line spectra are reduced considerably in chaotic state.