Abstract: To improve the flotation separation of micro-fine (-15 μm) monazite and fluorite, the flotation test, XPS test, and microaggregation analysis were used to investigate the application effect and mechanism of the combined inhibitors sodium silicate + ethylenediamine tetraacetic acid (EDTA) and composite collectors octyl hydroxamic acid (OHA) + octylphenol ethoxylate (OP) in flotation tests. The results showed that employing the combined inhibitors and composite collectors for the artificial mixed ores of -15 μm monazite and fluorite with a mass ratio of 1 GA6FA 1, a flotation concentrate with a recovery of 80% monazite and 24.4% fluorite was obtained. Furthermore, as compared to results obtained with only a single inhibitor or collector, both the flotation recovery of monazite and the flotation separation of monazite from fluorite were significantly improved. Additionally, EDTA was able to complex and remove Ca²⁺ ions from the surface of monazite, as well as facilitate the selective inhibition of fluorite by inhibitors. OP and OHA could synergistically adsorb on monazite surface, promoting hydrophobic agglomeration of micro-fine monazite and thereby improving the flotation recovery of monazite.