Abstract: In order to assess the immobilization efficiency of heavy metals before and after leaching with acid rain, changes of soil pH, availability of Cu, Cd, Pb and P and their chemical fractions under simulated acid rain (SAR) with pH of 3.5, 4.5 and 5.6 were investigated through a leaching experiment for phosphorus-based materials amended soil. Results show that applications of potassium dihydrogen phosphate (PDP) and hydroxyapatite (HAP) significantly increased soil pH and available P, and decreased available Cu, Cd, and Pb by the transformation of them from the active fractions to the inactive ones. Soil pH values in PDP-3.5 and HAP-3.5 treated soils were decreased by 0.45 and 0.47 unit than PDP and HAP soils, respectively. Available P was decreased and available of Cu and Cd were increased in PDP treated columns with leaching of SAR(P<0.05). Soil total Cu in HAP treated columns and total Cd in control columns were decreased by 14.5%-15.9% and 20.4%-26.5%, respectively, and exchangeable fraction of Cu and Pb in HAP and PDP treated columns were increased with leaching of SAR. Soil total P, resin-P, HCl-P, and residual-P were increased with the application of HAP and PDP. Soil resin-P and total P, however, were decreased in PDP treated columns, and stable P was increased significantly in HAP and PDP treated columns after leaching with SAR(P<0.05). The findings of the study indicated higher immobilization efficiency of Cu, Cd, and Pb and lower release risk of P was found in HAP than PDP under leaching of SAR.