本文介绍了BEPC工程(北京正负电子对撞机)同步辐射X射线光刻光束线真空系统设计。对反射镜箱的气载、系统的有效抽速及极限气压进行了分析和计算,并简要论述了有关的一些超高真空工艺问题。 This paper introduces the design of synchrotron radiation X-ray lithography beam line vacuum system of BEPC project (Beijing Electron Positron Collider). The airbag, the effective pumping speed and the ultimate pressure of the mirror box are analyzed and calculated, and some relevant ultra-high vacuum process problems are briefly discussed.