空调系统对制药厂的生产洁净区起着十分重要的作用，为了实现药厂空调系统的高效运行，以S7－300 PLC 为核心设计了空调控制系统。结合实际运行可能出现的异常情况，给出了故障诊断的实现方法。从汉江药业集团的实际运行效果来看，该系统安全可靠， 维护方便快捷。 关键词 PLC 空调设备故障诊断 Abstract Air-condition System plays an important role in drug factory for manufactory environment. In order to realize the high efficiency run of air-condition, a control system is designed using S7-300 PLC. Considering the abnormity of equipment in practice, this paper also gives the method to fault diagnosing. From the system effect in Hanjiang Drug Corporation, we can see that this control system is characterized of security, credibility and easy to maintenance. Keywords PLC，Air-condition equipment，Fault diagnose;