Abstract: Recleaning of liberated coking coal middling is of great significance for the recovery of scarce coking coal resource. The jig middling produce by a coking coal preparation plant under Hebi Coal and Electricity Co. Ltd. is taken as the object to conduct the experimental study on enhancement of flotation of the middling through in-depth grinding liberation and use of compound reagents. As shown by study results, with the middling crushed down to a size of < 0.5 mm, it contains a higher proportion of interlocked grains and lower proportion of suitable sizes of particles; at an optimum grinding time of 3 minutes, a maximum corresponding yield of flotation concentrate can be obtained while the yield of the < 0.074 mm sizes in the ground product is as high as 66.22%; with the use of 1600 ternary collector and Q7 frother at a respective dosage of 500 g/t and 150 g/t, the optimal flotation indices can be expected; and through one roughing and one cleaning processes, the concentrate with a yield of 53.83% and an ash of 10.25% can be produced, well demonstrating the effectiveness of recleaning of jig middling after it is thoroughly liberated through deep grinding.