By laboratory leaching experiments with the red soil from Zhejiang province, the effects of acid rain on aggregate and its cemedins of the red soil were studied. The results show that acid rain reduces the stability of red soil aggregate, increase its rate of structure destruction, decreases organic matter contain, and enhances activity of ferric oxide. These effects become more serious as falling of pH value and lasting of leaching time. The stability and structure of soil aggregate getting bad, which can accelerate soil erosion, shows that acid rain has soil erodibility.