Abstract: The industrial application of 650kt/a ethyl benzene complete technology developed by Research Institute of Petroleum Processing has been conducted on PO/SM plant in Ningbo ZRCC LYONDELL Chemical Company. The results show that both alkylation catalyst and transalkylation catalyst display its good activity and stability when the ratio of benzene to ethylene and benzene to diethylbenzene are 3.1 and 8.0, respectively. In alkylation reaction, the ethylene conversion is 100%, the average ethyl-benzene selectivity is 86%, and the average ethylation is high up to 99.5%. In transalkylation reaction, the average diethylbenzene conversion is 75% and the average ethyl-benzene selectivity reaches to 99.5%. The process flow and equipment design are both successful, and the consumption of energy and material are reduced. The quality of ethyl benzene can meet the requirement of PO / SM plant for a long-term stable running.