Abstract:The biogeochemical absorption of outer source iodine by spinach through fertilizing solid iodine in soil and spraying of liquid outer iodine in spinach leaves was studied. The result indicates that the iodine content in spinach increased with increasing outer source iodine rates and the application patterns of outer source iodine markedly affected the iodine absorption of spinach. The result also showed that most of iodine retain in spinach leaves by foliage dressing which indicated that iodine was not a recurrence element in spinach.