The invention provides a blast furnace coal injection automatic control method. The blast furnace coal injection automatic control method comprises the following steps: in the blast furnace coal powder injecting process, a blast furnace coal powder injecting process fluidization control method is adopted to fluidize coal powder in an injection tank; a coal injecting quantity automatic adjusting method is adopted to adjust the coal injecting quantity of a blast furnace; a monitoring method of a real-time coal injecting rate is adopted to monitor the coal injecting rate of the blast furnace, wherein the coal injecting quantity automatic adjusting method comprises the following steps: (A) the coal injecting rate of the injection tank and the tank pressure of the injection tank are set according to working conditions; and (B) under the set tank pressure, an actual coal injecting rate of the injection tank is stabilized in a set value range by adjusting the coal injecting rate of the injection tank through adjusting an air supply flow. The method finally enables the fluctuation of the coal injecting rate to be less than 2 t/h, achieves the coal injecting quantity automatic control conditions, reaches the hour coal injecting quantity error of about 0.3%, and provides conditions for stable production.