In order to ensure the oil supply,the precision of the hydraulic oil filter device for blowout preventer(BOP) control system is low,and the filter device is only installed in the oil absorption pipe and oil supply pipe,which result in the pollutants that generated in the system and invaded the system to enter the oil tank,causing the serious pollution of hydraulic oil.The shortcomings of the current BOP filter configuration were analyzed,such that the precision of the filter in the oil supply pipe is low,the straightthrough filter core of the high pressure filter has smaller capacity,is easy to block,and is inconvenient to clean and replace quickly,there is no filter device in the oil return pipe.Based on the regular BOP control system,a new online return pipe filter device and a independent external circulation pipe filter unit were designed.The field application shows that the new filter device can effectively improve the accuracy of hydraulic oil filtration and has no influence on the oil supply.