Abstract: Due to the alternate variation of soil redox potential and the particularity of soil components in paddy field, the selenium (Se) cycling and transformation in paddy soil are obviously different from those in upland soil, and can affect the Se availability in soil and the Se absorption and accumulation by rice. To deeply understand the Se cycling and transformation in paddy soil and the Se absorption and accumulation by rice is of great importance in studying the transformation of soil inorganic Se to organic Se. This paper summarized the researches on the cycling mechanisms and form transformation of Se in paddy soil and the metabolic mechanisms and absorption characteristics of Se by rice, and discussed the present status and development trend of the studies on the Se-transformation in soil-rice system and the Se translocation in rice plant, which could provide references for the study of soil Se availability and the cultivation of Se-enriched rice.