The release and form distribution, transformation of Cd in different Cd polluted soils affected by simulated acid rain were studied by pot experiment. The results showed that the growth of ryegrass was inhibited, and the total content of Cd increased obviously as increasing acidity of simulated acid rain and Cd concentration in soil. The content of Cd in root was higher than in overground parts. The quantity of active fraction of Cd in soils increased, and the active ability enhanced with the increase of rain acidy. Also, the main Cd was of exchange form in soil, and bioavailable form of Cd increased markedly. In a short time, simulated acid rain and Cd are all harmful to ryegrass, and the effect of Cd is more serious than simulated acid rain.The combined effects of Cd and simulated acid rain on environment are more harmful than Cd and simulated acid rain individual.