Abstract: In order to solve the problems of low concentrate yield and high ash content of concentrate which can not reach the qualified quality requirements (ash content of concentrate <12%) by conventional flotation process for Longquan 4# floating slime, the multi-stage flotation process was explored. The "one rougher, one cleaner" two-stage flotation tests revealed that the entrainment of high-ash fine slimes led to elevated ash content in the concentrate. Due to the high-shear flocculation flotation demonstrated a significant improvement in reducing fine slime entrainment, the "high-shear flocculation flotation +one rougher , two cleaner" flotation process combined with a reasonable flotation reagent system was adopted. The mechanisms underlying the improvement in flotation efficiency due to high-shear flocculation were analyzed using laser particle size analyzer, contact angle measuring instrument, scanning electron microscopy, and calculations of the collision probability between coal particles and oil droplets. The results indicated that using the flotation process of " high-shear flocculation flotation +one rougher, two cleaner ", the concentrate ash content of Longquan 4# difficult-to-floate coking slime can be reduced to 11.73%, the concentrate recovery rate reached approximately 50%, and the tail coal ash content can be increased to 82.57%. Both the concentrate and the tail coal index can meet the requirements of coal preparation plant.