In order to achieve high accuracy, less machining time, and more machining variety, normally, additional two rotary axes are set up on top of traditional three- axis CNC machine tool, which is called five-axis machines. The tool motion for five-axis machines in this research includes both translating and rotating axis movements simultaneously. This research analyzes the contour errors for multi-axis machine tools that have coordinated motion for both rotating and translating axes. This error depends on the setup of the machine, the distance between the center of rotating axis and the workpiece, and the increment of the rotating axis. A computer software program is developed to calculate the contour errors and simulate actual tool trajectory for multi-axis machine tools. This contour error analyses can be used to produce more accurate 5-axis tool paths for the advanced CAD/CAM system. A demonstrated example is provided to implement the tool trajectory error analyses for five-axis machining.