Abstract: Through analyzing the mechanism of low temperature corrosion of home-made heat medium heater and its harm to the in-line oil pipeline, it is pointed out that the temperature of heater tube is important factor to form acid dew point corrosion, which constrains seriously the gas discharge temperature in a low temperature way. Therefore, anti -low temperature corrosion material can be adopted to inhibit the corrosion, and other corrosion control measures include increasing the air inlet temperature decreasing the dew point of water vapour, varying convective heat-transfer coefficient, using hot-tube air preheater.