Grinding, an essential procedure before flotation, to some extent, determines the flotation behavior of minerals. In this study, the effect of grinding media on the flotation behavior of fluorite using sodium oleate (NaOl) as a collector was investigated via micro-flotation experiments, zeta potential measurements, scanning electron microscopy-energy dispersive spectrometry (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analyses. The results indicated that, compared with the fluorite particles ground by ceramic media, the ones ground by cast iron media adsorbed less NaOl, resulting in lower flotation recovery. The lower flotation recovery of fluorite particles ground by cast iron media resulted from the coating of the hydrophilic Fe precipitates generated in the grinding, including Fe(0), Fe(OH)2, and Fe(OH)3 on their surfaces. These Fe precipitates may cover the Ca active sites and increase the hydration membrane which can inhibit the further NaOl adsorption. This research reveals the effect of grinding media on the flotation behavior of fluorite and guides for media selection in disposing of fluorite ore.