A comparative study was conducted on laboratory nanobubble flotation and conventional flotation for fine crushed ore samples from an ore-dressing plant. The study investigated the effects of different reagent dosages on the flotation performance of microfine-grained gold ore,with -0.074 mm particles accounting for 92 % of the sample. The results showed that nanobubble flotation significantly improved the Au grade and Au recovery of gold concentrate,as well as the flotation rate. In a closed-circuit flotation process with once roughing,three times cleaning,and twice scavenging,nanobubble flotation achieved a concentrate with an Au grade of 35.32 g/t and a recovery rate of 93.11 %.Compared with conventional flotation,the introduction of nanobubbles increased the Au grade of the concentrate by 3 g/t and the Au recovery rate by 12.33 percentage points. Based on atomic force microscopy and laser particle size analysis,it was proposed that nanobubbles generated by cavitation preferentially form on the hydrophobic surface of pyrite and induce hydrophobic agglomeration,thereby improving the separation of fine-grained minerals.