A virtual prototype model of five-axis CNC machine tool has been constructed. Through the ADAMS software, the process of the machine is simulated and the dynamic analysis is carried out. The experimental model analysis on the column of the machine is practised with the software ADAMS, the weak link of the column is found out and a modification scheme is put forward for the design of the column structure. Improvement of structure of the column can effectively raise the working accuracy .Currently, five-axis CNC machine tool is the only way to solve parts processing such as impeller, special propeller, turbine rotor , large diesel engine crankshaft ,etc. Therefore, it is very important to carry out the dynamic analysis of the five axis CNC machine. In this paper, a rigid-flexible multi-body dynamics model for a five-axis CNC machine tool is set up, in which the column parts are modeled by flexible bodies. Aimed at the improvement of the machining accuracy, the effect of different structures of column are analyzed.