The effects and mechanism of different concentration organic acids and organic salts solution on Al availability of dark brown forest soil were studied. It was resulted that, oxalic acid/oxalate and citric acid/citrate substantially stimulated soil Al release of dark brown forest soil. The effect of organic acids/salts on Al release would be strengthen with increasing of their concentrations.The contents of Al released from A1 horizon was higher than that from B horizon. Organic salt solutions had much higher effects than organic acid the same in concentration, i.e. citrate>citric acid, oxalate>oxalic acid. Therefore, the mechanism of organic acid/salts triggering release of soil Al was assumed to be dominated by complexation reactions of organic anions. Citric acid/ citrate had much higher effect than oxalic acid/ oxalate at same concentration to A1 and B horizons, i.e. citrate> oxalate, citric acid>oxalic acid, which was primarily related with the greater complexing capacities and dissociation constants of citric acid.