Abstract: To improve the poor flotation performance of fine molybdenite under conventional flotation conditions, hydrophobically modified magnetite was used as a carrier mineral, and its effect on the flotation performance of fine molybdenite was investigated. Natural magnetite was modified using sodium oleate (NaOL), and a hydrophobic magnetic carrier with a contact angle of 120.77° was successfully prepared. Single−mineral flotation tests were conducted to examine the effects of carrier dosage, stirring speed, stirring time, collector dosage, and frother dosage on the recovery of fine molybdenite. In addition, flotation kinetics and real−time particle size monitoring were employed to reveal the strengthening mechanism of the hydrophobic magnetic carrier. The results show that under the optimum conditions, namely a carrier−to−molybdenite mass ratio of 80%, a stirring speed of 1800 r/min, a stirring time of 4 min, a kerosene dosage of 60 mg/L, and a 2# oil dosage of 50 mg/L, the recovery of fine molybdenite reach 83.17%, which is 26.54 percentage points higher than that of conventional flotation. The flotation kinetics results indicat that carrier flotation significantly enhanc both the recovery rate and the final cumulative recovery of fine molybdenite. Bench−scale flotation tests of real ore show that carrier flotation can significantly improve flotation indexes.Real−time particle size monitoring demonstrat that the hydrophobic magnetic carrier effectively captur fine molybdenite through hydrophobic association and promot the formation of abundant and relatively stable composite agglomerates in the size range of 10~100 μm, thereby markedly improving the flotation performance of fine molybdenite. These results demonstrate that hydrophobic magnetic carrier flotation is an effective approach for enhancing the recovery of fine molybdenite. EDLVO calculation analysis shows that in the carrier flotation system, the total interaction energy between particles presents a strong attractive state. The attractive force increases sharply when the particle spacing is less than 20 nm, which provides a crucial driving force for the heterogeneous aggregation of fine molybdenite on the carrier surface, and ultimately realizes the effective aggregation and flotation recovery of fine particles.