Abstract: In order to research effect of low temperature stress on antioxidant enzyme system and osmotic regulation of different genotypes maize seedlings. Resistant variety (xianyu 335) and sensitive variety (fenghe 1) were selected in the research and room temperature treatment (CK) and low temperature treatment (L) were set. Potted plants were used in the research, and random design. The aim of research is to provide a theoretical basis for study of cold resistance physiological. The results are as follow: maize morphogenesis was affected by low temperature, and plant height, leaf area, dry matter, root length, root surface area and root volume were decrease. Compared to ‘fenghe 1’, ‘xianyu 335’ showed less descending value in the above indicators. MDA and和O2.- content were increased significantly, and ‘xianyu 335’ showed less accumulation of malondialdehyde (MDA) and superoxide anion (O2.-) content than ‘fenghe 1’. With the accumulation of harmful substance, superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) activity in leaf were increased which could remove harmful substances, protect the cell membrane. The enzyme activity of ‘xianyu 335’ rose faster than ‘fenghe 1’ in low temperature stress. Low temperature stress could increase soluble protein, soluble sugar and proline, which was benefited for maintaining the pressure in cell, reducing damage. Physiological metabolism of maize could be regulated for reducing low temperature damage.