Abstract: We tentatively addressed the problem that the expensive,imported multi-stage compound vacuum generator(MCVG) of robots easily breaks down or frequently deteriorates ahead of its short service-life,because of mis-operation and poor-maintenance. In addition to the Dos and DONOTs listed in the manual,the discussions with specific example focused on:i) Diagnosis of the common mal-functions of MCVC,including,but not limited to the increasing output-pressure,deformation and dust-deposition on the plastic high-speed air-pipe walls; ii) Theoretical analysis and experimental evaluation of the reasons for the mal-functions at an early usage; and iii) Effective preventions and solutions to the mal-functions. For example,a diameter of the air-pipe smaller than ф0.8 mm should be cleaned or replaced,because a thinner diameter significantly increases the lowest output-pressure of MCVG at Standard Industrial Air-pressure of 0.6 MPa.