机床主轴系统是机床的核心部件，其热特性的好坏，直接影响机床的加工精度；以建立主轴系统的有限元模型，结合主轴系统与普通水箱之间的冷却模型，对带有冷却套的主轴系统进行了热特性分析，得出了主轴系统的热特性曲线；根据分析结果，对XK717数控铣床主轴部件冷却套的布局进行了改进设计，为优化数控铣床主轴系统提供了理论依据。

The main spindle system is a key part on the machine tools. The quality of thermal behavior influences the machining accuracy of machine tools directly. In this paper, thermal characteristics of spindle system on the XK717 CNC milling machine are analyzed by combining finite element method with cooling model between spindle system and water tank. Effect rule to thermal characteristics of the main spindle system are obtained. The cooling jacket on the main spindle is improved by the results. This research provides the theoretical fundamentals for optimization design of CNC milling machine.