Abstract: With the digital imaging processing, the bubbles imaging in flotation column were obtained.By adopting the image processing software of Pro Plus 5.0, the size and the diameter distribution of bubbles are calculated, and the effect of mean size and wettability of foaming generator, superficial gas velocity on the size of the bubbles were studied.The results showed that Sauter diameter of the bubbles decreases with the decrease of superficial gas velocity and mean size of foaming generator, and wettability of foaming generator has obvious effect on the size of bubble.Compared with hydrophobic foaming generator, it is easier to produce micro-bubble for hydrophilic foaming generator.The bubbles produced by foaming generator which with smaller pore and hydrophobic material are beneficial for the recovery of fine particles by flotation.