The invention relates to a method for setting a coal injection rate of a blast furnace, belonging to the technical field of iron-making of blast furnaces. On the basis of the deviation of a predictive value and a target value of the silicon content in molten iron, the method is used for calculating the corresponding comprehensive coke ratio adjustment amount, calculating a new coal ratio in combination with the original coal ratio, calculating the coal injection rate to be set currently by finally utilizing the new coal ratio and a current molten iron generation rate value, displaying calculation results in a compared manner, and providing assistant operation for artificially setting the coal injection rate. The method for setting the coal injection rate of the blast furnace provided by the invention is capable of rapidly calculating the coal injection rate required by production and assisting an operator to increase the timeliness and the accuracy for setting the coal injection rate; incorrect operation is effectively avoided; and automatic control is realized by setting an auxiliary system through the coal injection rate of the blast furnace.