Acidified water glass shows selective depression for calcite, which allowing preferential flotation separation of barite from calcite when using sodium oleate (NaOl) as collector. Display omitted Flotation separation of the barite from calcite by adding depressant acidified water glass (AWG) and collector sodium oleate (NaOl) was investigated in this study. The micro-flotation results presented that NaOl has a good collecting ability for both barite and calcite while AWG has the selective depressing ability of calcite. The flotation of artificial mixed minerals confirmed that the separation of barite from calcite could be achieved by using AWG as depressant. Zeta potential revealed that the addition of AWG prior to NaOl prevented the adsorption of NaOl on the surface of calcite while it did not hinder NaOl absorbed on the surface of barite, then causing the different floatability of minerals.