Abstract: The study on the effect of floatation reagent BET on coal and pyrite, which mainly concerned the respects such as surface potential, wettability, ESCA analysis and absorption measurement of coal and pyrite, revealed the mechanism of BET to coal and pyrite. The separation tests of practical samples were carried out. The results manitest that the floatation effect of BET is better than that of other common floatation reagents and has a higher selectivity especially in high-sulfur coal sample floatation.