Samples of Fe-leachi-Stagnic Anthrosols were collected and incubated with different rates of CaCO3 and H2SO4 amended through titration, for indoor simulation of variation of the pH buffering capacity of the soil as affected by rainfall, different in pH (2.5, 4.5 and 6.5) and nitrogen application, different in rate (0, 150 mg kg^-1 and 300 mg kg^-1), and further for exploration of effects of rainfall and N application on soil total acid induced and on leaching of mineral N. Results show that soil acidification rate ranged from 4.73 mmol H⁺ to 15.57 mmol H⁺ per column, being the lowest in the treatment with rainfall 6.5 in pH and N application zero and the highest in the treatment with rainfall 2.5 in pH and N application rate N2. Soil acidification rate increased with N application rate, regardless of pH of rainfall. In the treatment with zero N application rate, soil acid accumulated with decreasing pH in rainfall. In the treatments with N application rate being, soil acid accumulation was the highest when the rainfall was 2.5 in pH, and the lowest when the rainfall was 4.5 in pH. Leaching of nitrate induced soil acidification and the amount of acid induced by leaching of nitrate ranged from 4.24 to 13.18 mmol per column in the experiment, while leaching of NH₄⁺ consumed H⁺ at a rate of 0.01 to 0.29 mmol per column. In the treatment with rainfall normal in pH, 6.5, N application at 15 mg kg^-1 and 30 mg kg^-1 increased soil acid by 11.34 mmol and 12.96 mmol per column, respectively, which was more than it did in the treatment with rainfall 2.5 in pH (9.49 mmol per column), and in the treatment with rainfall 4.5 pH (6.87 mmol per column) and more than the amount of H⁺ rainfall 4.5 in pH brought in (0.16 mmol per column). The above findings show that application of nitrogen alone may induce more acid than acid depostion with rainfall could bring in. However, no matter whether rainfall or N application, leaching of NO₃^- plays a leading role in accelerating soil acidification.