Abstract: Failure of packing ring of compressor set will result in shutting down. A comprehensive analysis on failure cause of packing ring is carried out from aspects of composition of packing box and running process, and relevant improvement and preventive measures are presented. It is found out that improvement measures taken in centering of packing box and cylinder rod, decreasing temperature of cooling water, replacing variety of lubricant and increasing injection rate of lubricant can effectively increase running efficiency of compressor sets.