Abstract: In order to find best operating point of 1. 6 m double mass horizontal vibrating centrifuge,established three-dimensional model,modal analysis of this model is carried out as well as response is studied in condition of simple harmonic exciting force. The result shows: ideally,very small axial vibration displacement of primary vibrating body is obtained at 24 Hz four-order natural frequency,while getting bigger displacement of secondary vibrating body; in forced vibration,it is proved to reasonably determine operating point of this centrifuge by vibration mode of primary and secondary vibrating body or amplitude curves in different exciting frequency and different ratios of stiffness.