Abstract: Surface oil/gas processing system used in old oilfield directly limits itself development due to backward technology, low operating efficiency and high energy consumption. In the paper, distribution, processing capacity, operating efficiency and aging degree of facilities in Chaheji Oilfield are described and overall restructuring on the functions of processing stations are carried out based on requirements of secondary development for oil/gas processing, that is, HB -L1 low-temperature demulsifier is optimized, which decrease the pressure settlement dehydration temperature by 7 ℃; average crude oil moisture content after settlement dehydration is less than 0.5% through improving internal structure of settling tank, which meets transport standard; automatic monitoring system in the station is improved and upgraded.Test and comparison results before and after the restructuring show that the station system efficiency is improved by 10% and energy consumption is reduced by 15% to reduce the number of operating personnel to improve production safety.