Abstract: Bubble characteristics and its influence factors in electroflotation with aluminum were studied in a homemade electrode-separated electroflotation column, which is aiming to provide a theoretical foundation and data support for the utilization of electroflotation. The effects of solution pH, voltage strength and electrode reaction time on bubble size and concentration were investigated. The correlation of bubble rising velocity and bubble size was explored. The results indicated that the size of hydrogen bubbles from cathode was less than 100 μm. The impact of solution pH value, voltage strength and electrode reaction time was significant on bubble size and its concentration. The primary impact factor (i.e. electrode reaction rate) decided the time of a bubble breaking away from electrode plate and the bubble accumulation per unit time. The higher the electrode reaction rate was, the smaller the bubble size would be, resulting in higher concentrate and lower rising velocity.