Abstract: Based on the response surface method, the speed of the impeller and the volume of the flotation cell in the self-aerated flotation machine are studied, and the influence of energy input on the performance of coal flotation is studied. The analysis of raw coal properties shows that raw coal contains 42.3% fixed carbon, 20.4% volatile, 2.7% moisture and 34.7% ash. The relationship between variable factors （impeller speed and cell volume and interaction） and indexes （yield, ash, fuel recovery and entrainment water recovery） was established by using three-level and two-factor experiment design. The test results show that the recovery rate of ash and entrainment water increases with the increase of impeller speed. At higher impeller speed, the coal yield and combustible recovery rate in 2 L flotation cell are lower. However, at a lower impeller speed, the coal yield and the recovery rate of combustible body in the 6 L flotation cell are lower. In a 4 L flotation cell, the maximum combustible recovery rate of 72 % was obtained at 1 500 rpm. The experimental data were used to build a fitting model, and ANOVA was used to analyze factor significance. The R² values of the primary model were 0.94 and 0.97, respectively.