In order to investigate the dynamic properties of a new air bearing rotor system, a modal experiment plan with one fixed acoustic response and roving impact excitations was adopted to get the first two lateral vibration freque ncies and damping ratios of the rotor, which provided references for the fault diagnosis and speeds control of the system. The pressure distribution features at static pressure orifices were extracted by characterizing the lubrication and stability properties of the new graphite bearing with the finite difference method, the rigid mode and support characteristics were gotten, and rub-impact fault in the axial direction and its causes were discovered in the startup and coastdown procedures.