This study examined the role of gum arabic (GA) as a depressant in the flotation separation of fine-grained scheelite and calcite using flotation and adsorption tests, Zeta potential and contact angle measurements, and X-ray photoelectron spectroscopy (XPS). Microbubbles were introduced to improve the flotation separation of scheelite and calcite, addressing the poor flotation performance of fine-grained minerals. In the pH 9 slurry, GA significantly depress calcite while having minimal effect on scheelite. A concentrate with a WO₃ grade of 60.47% and a recovery of 74.29% was achieved using GA and sodium oleate as the depressant and collector for a 1:1 mixed mineral. Adsorption tests indicated that scheelite adsorbed less GA on its surface compared to calcite. Contact angle measurements demonstrated that GA altered calcite's wettability, rendering it hydrophilic. XPS analysis indicated that GA formed a chemical interaction with the surface Ca²⁺ ions of calcite, whereas it exhibited weak physical adsorption on scheelite. Zeta potential measurements revealed selective chemical adsorption of GA anions on fine-grained calcite surfaces. In conclusion, the inhibition mechanism of GA on calcite is related to the chemical chelation with surface Ca²⁺, enabling the efficient flotation separation of fine-grained scheelite and calcite, and the introduction of microbubbles can enhance the recovery of scheelite.