Abstract: Excessive heavy metals in cultivated land directly affects the quality of crops and irrigation water, and therefore human health. By investigating the contents and phase states of arsenic and cadmium in irrigation water, chemical fertilizers, crops and root soil around Baotou industrial zone in Inner Mongolia, the paper studies the transformation and enrichment rules of As and Cd. The results show that the soil and irrigation water are weakly alkaline, and the contents of As and Cd in irrigation water and fertilizer are in accordance with national standards. The As contents in root soil and edible parts of corn, sunflower, cabbage and green onion are all below the limit by official standards, mainly existed in the form of residual state. The Cd contents in the root soil of the four crops above exceed the standard in different degrees. Except for 50% exceeding of Cd in sunflower seeds, the edible parts of other crops are below limit. It is found that the excessive Cd in sunflower seeds is because Cd is mainly occurred in carbonate and humic acid forms and the enrichment of Cd in sunflower seeds is higher than that in other plants.