As a pretreatment technology of coal slime flotation, High Intensity Conditioning has a positive effect on the strengthening of flotation process. In this study, a series of slurry mixing and flotation tests were carried out on coal samples from Hulusu Coal Mine in Tuke Town, Udeng Banner, Ordos City, Inner Mongolia Autonomous Region to study the effect of high shear slurry mixing pretreatment on coal flotation. The results show that the recovery rate of high shear slurry flotation was 3.79% higher than that of conventional flotation combustible mixture under FDJ and Q1. In the case of similar combustible recovery, the amount of collector can be saved by 37.5%. The test results of flotation kinetics tests show that after high-shear slurry conditioning pretreatment, the combustible recovery rate increased by 20.02% and 25.99% respectively in the first two 20 s. The flotation process was completed at 90 s. The flotation velocity constant increased by nearly 50%. Under the combination of EKOF and Secoctanol, the strong shear force and eddy current effect will make the foaming agent composition in the composite agent play a role in the mixing stage. The bubbles carry coal particles to float, and carry drugs those are not dispersed in time, which causes waste of drugs and worsens the flotation effect.