This paper introduces the application of the three-stage cross tube primary cooler in Bayuquan Ansteel.It analyzes the causes of the blockage of the primary cooler and the increase of the resistance.It also puts forward the solution of cleaning the primary cooler with hot wash oil,and optimizes this technology in production.As a result,solutions were given to problems,such as to remove the blockage in the primary cooler,to lower the gas resistance,to reduce the load of gas exhauster,and to prevent coke oven from bleeding due to the insufficient suction in front of the primary cooler.