In this work, the effect of fenugreek-gum (FG) on the depression of talc with different particle sizes and the depression mechanism were systematically investigated. The floatability of talc was influenced by the granularity, and the floatability of talc in different particle sizes followed the order: -0.074+0.037mm > -0.037mm > -0.010mm. FG had a strong depressing effect on talc, especially for coarse talc, the -0.074+0.037mm size fraction of talc was completely depressed by 2.5 mg/ dm3 FG. The depressing effect of FG for talc was influenced by particle size. Larger dosage of FG was needed in order to completely depress talc with smaller particle size. The absolute value of talc surface charge and the inter-particle repulsion decreased in the presence of FG, causing easier inter-particle flocculation. FG interacted with talc surface by chemical adsorption.