介绍国产引进型300MW汽轮机轴封系统的工作原理，针对其普遍存在的轴封加热器真空不足、运行方式不合理、供汽自动调节性能不良而导致汽轮机真空严密性差、轴端冒汽、润滑油带水等一系列问题，通过对嘉兴电厂2台机组轴封系统的现场试验和理论分析，找到了问题的根本原因，经技术改进和运行优化，有效地提高了机组运行的安全性和经济性。 The working principle of the shaft sealing system of domestic imported 300 MW steam turbine is introduced. In view of its ubiquitous lack of vacuum in the shaft sealing heater, the operation mode is unreasonable, the steam regulating performance is poor and the vacuum tightness of the steam turbine is poor. Water and a series of problems. Through the field test and theoretical analysis of the shaft seal system of 2 units in Jiaxing Power Plant, the root cause of the problem was found. After technical improvement and operation optimization, the safety and economy of the unit operation were effectively improved .