Selenium is one of the essential elements for plant growth and has important physiological functions in plants. With the improvement of living standard, and the important role of selenium in human health has been concerned, thereby selenium-rich agricultural products has become one of the hot spots in scientific research and agricultural production. In this paper, the existing forms of selenium in soil and plants, the main physiological functions together with the absorption and utilization of selenium in crops and the regulation of biological enrichment were summarized, and also the future research was prospected. The purpose of this review was to provide theoretical technology and references for the efficient utilization of selenium resources.