Based on the characters of Chinese bauxite resources,the separation of diaspore and gangue mineral by reverse flotation was studied preliminarily in this paper.The reverse flotation experiment on hardly-treated high silica bauxite using BS-1 as combined collector and TZ-1 as regulator under moderately acidic condition was carried out,and the A/S of concentrate was up to 10.01,comprehensive recovery rate of alumina reached 83.13%.