Abstract: The primary constituents of discarded drilling fluid are barite, quartz, and calcite. However, during the flotation process, these three minerals exhibit similar physicochemical properties, complicating the separation and recovery of barite. To address this, a novel composite inhibitor (WFF) was developed, consisiting of guar gum (GG), β-cyclodextrin, and ferrous sulfate (FeSO₄), using sodium dodecyl sulfate (SDS) as the collector for flotation. Through reverse flotation experiments, barite concentrate with a density of 4.11 g/cm³ and a purity of 91.86% was successfully recovered from the discarded drilling fluid. In addition, the mechanism of action of WFF was elucidated using infrared spectroscopy, X-ray diffraction analysis, X-ray fluorescence spectroscopy, adsorption capacity measurement, wettability, and surface tension tests. The results indicated that WFF selectively adsorbed on quartz and calcite, enhancing the adsorption performance of SDS on these two minerals, while barely affecting the flotation performance of barite. This enabled efficient flotation recovery of barite from discarded drilling fluid.