Selenium is an essential functional element of the human body, and the issue of selenium accompanying heavy metals is receiving much concern. This paper expounded the form of existence of selenium and cadmium in soil and influencing factors of their bioavailability, and further elaborated the interaction between selenium and cadmium. On the basis, it provided references for further studies on the interaction between selenium and cadmium, and provided basis for establishing selenium-enriched barrier technology for crops.