Abstract: By taking the propylene polymerization process as the research object，a method of constructing the knowledge base of the abnormal situation self-recovery system was presented. By applying the results of hazard and operability analysis，mechanism model and related accident cases to the propylene polymerization process，a technical basis for condition monitoring，early warning and self-recovery was established. Based on the results of hazard and operability analysis，alarm rules were formulated，the temperature，pressure，flow rate and liquid level of the process could be real-time monitored，and non-monitored variables could be calculated to give in-time alarm，reasons for abnormal situation，consequences，and preventive measures，which may be important for maintaining normal production.