To mitigate ammonium pollution and soil acidification associated with traditional (NH₄)₂SO₄ leaching of ionic rare earth ores, a synergistic approach utilizing low-concentration (NH₄)₂SO₄ and acetic acid (HAc) was proposed to enhance ion exchange efficiency while minimizing ammonium consumption. Leaching efficiency and ammonium consumption were evaluated through comparative leaching experiments. Under optimized co-leaching conditions (pH 4−5, 30 °C, and 1 h), rare earth elements (REEs) leaching efficiency of 88.92% was achieved. This represents a  13.36% increase over single (NH₄)₂SO₄ leaching (0.02 mol/L). Compared to the conventional single (NH₄)₂SO₄ system (requiring 0.03 mol/L for 90% efficiency), ammonium consumption was reduced by 33.3%. Characterization revealed enhanced surface roughness and significantly increased negative charge on the ore in the synergistic system, facilitating RE³⁺ exchange. This study provides a sustainable leaching approach, reducing the environmental impact of traditional REE extraction through the rational use of inorganic lixiviants.