The performance of computerized numerical control (CNC) machine tool is evaluated by the traditional positioning error and the positioning repeatability, which is in quasi static and cannot reflect the precision of machine tool in the process of movement and machining. In this paper, a novel precision evaluation method which takes the dynamic precision as index is proposed for high-speed machine tool. The precision of machine tool is described through the consistence of the actual trajectory and the ideal command. The specific evaluation index of dynamic precision is provided. Meanwhile, the measure method of evaluation index is put forward. It can be obtained that this new evaluation method of machine tool precision can evaluate the quality of key performance in CNC machine tool systematically and roundly.