The spindle system in a precision multi-shafting friction torque measuring instrument is one of the most important parts of the instrument, its vibration characteristic analysis is an important work in the design of the instrument. At first, the spindle system of the horizontal structure in the instrument is analyzed. The supporting shaft, the measuring shaft and the torque sensor are simplified to be a whole,the bearing supports are simulated by using the elastic supports. Then the 3D model of the spindle system is built with CATIA. Finally by using finite element analysis software ANSYS Workbench, the modal analysis of the spindle system simplified is carried out to obtain the natural frequencies,the vibration modes of the first 6 orders and the critical speeds. The results show that the the spindle system can effectively avoid the resonance region.The necessary basis for further dynamics analysis is also provided through the modal analysis.