A spectrophotometry based on the extraction of the 8-hydroxyquinoline complex (at pH8.3) into butyl acetate was introduced to determine the soluble Al in acid soil solutions. The linear range of the determination is from 0 to 50mmol/L with a significant correlation (R²:0.9999). The method is sensitive with an apparent molar absorptivity of 1.995×10⁴ L/(mol·cm). The results from recovery test showed that the recovery rate was from 98.7% to 106.8%.