The invention discloses a control method applied to a KR desulfurization method. The control method includes the following steps of firstly, moving a hot-metal bottle to a stirring position after conducting temperature measuring, sampling and drossing; secondly, transmitting hot metal parameters to a PLC, calculating the weight of needed desulfurizing agents, and discharging material to a weighing hopper through a material bin; thirdly, lowering a stirring head to make contact with the liquid surface of the hot metal, recording the height of the liquid surface of the hot metal and calculating the insertion depth through the PLC, lowering the stirring head to the insertion depth and making the stirring head rotate according to the speed-up curve; fourthly, lowering a feed chute, opening an air conveying valve, feeding the desulfurizing agents evenly in a segmented mode according to weights, and lifting the feed chute after feeding is completed; fifthly, controlling the stirring head to rotate to throw slag through the PLC after stirring is completed, and when the stirring head rotates till the slag throwing time, controlling the stirring head to stop throwing the slag and lifting the stirring head to a position where the stirring head is to be used through the PLC; sixthly, conducting drossing in a later period. The control method has the advantages of being high in automation degree, capable of shortening the time consumed for the desulfurization procedure, high in production efficiency, low in hot metal temperature drop and low in failure rate, and can be widely applied to the technical field of hot metal preprocessing.