The soil samples of 3 types of red soils, which developed from Quaternary Red Clay, the weathering product of slate, and the weathering product of limestone in the hills of Southern Hunan, were collected to study the total concentrations and chemical fractions of Cd in the soils by BCR sequential extraction and FAAS. The results showed that the concentrations of the different fractions of the 3 types of red soil follow the order of the residual fraction>the acetic extractable fraction>the acid reducible fraction>the organic fraction. The concentrations of the acetic extractable cadmium ranged from 22% to 28%, which would be at medium risk to the environment according to risk assessment code for all the soil samples. Besides the form distribution of cadmium in the soil samples were closely related with soil pH and soil organic matters.