Abstract: The results from pot experiment showed that the drought tolerance mechanism of osmotic regulation and antioxidation was all found in sorghum and maize seedlings. The drought tolerance of sorghum is stronger than that of maize, its leaf relative water content and water potential are higher under drought condition. The main osmotic regulation substances in sorghum are soluble sugar and protein, catalase(CAT) is used as the main antioxidant enzyme. K⁺and proline are the main osmotic regulation substances and the main antioxidant enzymes are superoxide dismutase(SOD) and peroxidase(POD) in maize.