Formation, transformation and volatilization of organic iodine in soil are of great significance to iodine transport and transformation in nature, ecological safety and human health. Based on previous studies on iodine in soil, this paper presented the form and concent of iodine in the soil, focusing on the reaction mechanism between iodine and organic matter to produce organic iodine, the factors influencing the organization of iodine in soil and the volatilization of organic iodine in soil. IO₃^– and I^–in the soil undergo redox reactions to form intermediate substances HIO and I₂, which are transformed chemically and biologically to produce organic iodine. Soil pH, redox potential, organic matter content, enzyme activity, and concentration of Fe/Mn oxides and their hydroxides affect the formation and transformation of organic iodine. The volatilization of organic iodine is mainly through the process of producing volatile methyl iodine in vivo by microorganisms and higher plants.