Abstract: In this paper, the safety hazards of flare automatic control system were analyzed to ensure the safe and smooth operation of vent flares at liquefied natural gas (LNG) receiving stations. Then, the practical implementation scheme was put forward to deal with the quenching alarm delay of flare ever-burning lamp, the detection of flare igniter insulation, so as to prevent the vent of combustible gas from leading to safety accidents during the flare failure. It was recommended to install the low flow rate alarm of fuel gas and the high level interlock of condensate tank so as to diagnose and predict the abnormal operating conditions of flare unit in advance. As for the operation hazard of single flare during the maintenance of LNG flare unit in Qingdao, the cold and hot flares with mutual stand-by were realized by changing the control logic and process retrofit. By virtue of above mentioned analysis and retrofit on the safety hazards of flare control system, the flare unit can be kept more stable and reliable and the abnormal conditions can be avoided.