Abstract: In order to explore the interrelation of the primary and secondary factors and the optimum combination of operating parameters that influence the effects of slime flotation, the flotation feed of Xingtai Mine Coal Preparation Plant is taken as the object for case study, and tests are conducted on the levels of five selected factors of impeller speed, aeration quantity, feed concentration, dosage of collector and dosage of forther, using the Central Composite Design software (CCD). Meanwhile, the multi-element regression model is constructed with the ash and yield of flotation concentrate and ash of tailing as response values. Study results show that through analysis and optimization with the model, the effects on the performance of the flotation process produced by various factors and their interaction have been brought to light, and the optimum operating parameters of impeller speed, aeration quantity, feed concentration, dosage of collector and dosage of frother which are fit for flotation of the slime under test are 2310 r/min, 0.38 m³/h, 70.69 g/L, 448.21 g/t, 93.21 g/t,respectively.