Abstract: Heat efficiency theory of heaters is analyzed in the paper.It is pointed Out that measures to increase heat efficiency of heaters are to decrease flue gas loss, radiation loss, imperfect combustion loss of gas and solid.Based on the operation situation of GW5000-Y/6.4-Y2 Direct Fired Heater used in TieIing— Qinhuangdao Oil Pipeline, the measures included in technical reform program for the purpose of decreasing flue gas temperature of the heater, controlling the heater operating in high efficiency working ZOne and enhancing air tightness of heaters are provided.