The extraction and separation of rare earth element Y from coal fly ash leachate were systematically investigated using a simulated extraction system. A mixed chloride solution of pure La-Y was employed as the experimental object, with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) serving as the extractant. The extraction process of Y in the simulated rare earth solution and its optimal conditions were studied. Experimental results reveal that impurity ions Al³⁺ and Fe³⁺ exhibit competitive effects with Y³⁺, significantly reducing Y extraction efficiency. The optimal extraction conditions for Y from the simulated solution were determined as follows: room temperature, extraction agent volume fraction 3%, oil to water ratio (V_O∶ V_A) = 1∶ 1, solution pH of 1.6, extraction time of 25 minutes, and oscillation rate of 150 r/min. Under these conditions, the extraction rate of Y reaches 97.25%. Mechanistic studies identified the extracted complex composition as YCl₂H₃A₄ Kinetic analysis demonstrates that the extraction rate followed a nonlinear relationship with Y³⁺, P507, and HCl concentrations, consistent with the derived rate equation. Subsequent experiments were conducted using concentrated coal fly ash leachate instead of the simulated solution. Results show that after removing Fe³⁺ impurities, the extraction rate of Y under optimized conditions increases by over 60% to 82.89%. The overall rare earth extraction efficiency improves by more than 40%, reaching 67.73%. Furthermore, impurity removal effectively enhances the separation coefficients between Y and other rare earth elements, facilitating selective Y extraction from the leachate.