Abstract: This is an essay in the field of mineral processing engineering. Through micro-flotation experiment, contact Angle test, Zeta potential test, Adsorption measurements and infrared spectrum analysis, the effects of alendronate sodium on the flotation behavior of fluorite and calcite were studied, and the adsorption mechanism of alendronate sodium on the surface of two kinds of minerals was investigated. Micro-flotation experiment results show that when only sodium oleate is added, fluorite and calcite have good floatability in the pH range of 7~12 and are difficult to separate. The floatability of fluorite and calcite is different when sodium alendronate is added, and the flotation separation of fluorite and calcite can be realized. The results of contact Angle test, Zeta potential test, adsorption capacity test and infrared spectrum analysis showed that the adsorption amount of sodium alendronate on fluorite surface was less, which had little effect on its surface wettability, while the adsorption amount on calcite surface was larger, which had a greater effect on its surface wettability. Two phosphate groups in sodium alendronate bind with calcium atoms on the surface of calcite, which hindered the adsorption of oleic acid molecules on the surface of calcite, thus inhibiting the calcite.