Abstract：Based on sample collection and laboratory analysis, this paper studied the distribution features and genesis of Cd in soil of high content areas in Chengdu plain lying in the alluvium of Mianyuan River and Shiting River basin. The high content areas of Cd are distributed in alluvium of Terrace 1 and 2, and gradually decrease from Terrace 3 to Terrace 5. The content of Cd in alluvium along the two rivers developed in the Longmeng Mountain is remarkably higher than that of other water systems. The feature that the high content areas of Cd are consistent with different terraces indicate evidently that the evolution of geological processes served as a controlling factor. This conclusion is radically different from the opinion of most investigators that it resulted from human factors.