The cooling of LNG storage tank and pipeline is one of the most important links before the LNG terminal is put into operation.The cooling control model of LNG storage tank is established to monitor and analyze the temperature drop data of on-site storage tank to guide the cooling operation of storage tank,so as to control the cooling rate of LNG storage tank within a reasonable range and realize the stable cooling of storage tank.In view of different cooling sources,this paper summarizes the cooling operation methods of LNG pipelin,focuses on the research of the temperature drop law of unloading pipeline in LNG terminal,and puts forward the "intermittent" Liquid Nitrogrn Precooling method instead if BOG precooling method to precool the unloading pipeline,which can change the velocity of gas in the pipeline,and control the temperature difference between the upper and lower parts of the pipeline within the design value to achieve uniform mixing.This method can reduce the emission of BOG,save the debugging time and cost.The cooling control model of LNG tank and the liquid nitrogen cooling method of LNG pipeline have been well practiced and applied in the commissioning of projects in operation,which can be used as reference for the operators in the LNG industry.