Abstract: To explore the optimal cryopreservation conditions for Sinopodophyllum hexandrum seeds, and to provide technical support for the long-term preservation of S. hexandrum seeds, four kinds of seeds with different moisture contents（1.6%, 9.6%, 20.9% and 30.5%） were obtained by silica gel drying, natural shade drying and soaking methods, and cryopreserved by direct freezing, slow freezing and vitrification respectively, and the seed viability and the activity of superoxide dismutase（SOD）, peroxidase（POD）, and the contents of malondialdehyde（MDA）, total protein（TP）, soluble starch and soluble sugar in seeds were measured before and after cryopreservation respectively. The results showed that the seed viability of S.hexandrum seeds with different water content declined in varying degrees after three cryopreservation methods, but the seeds with water content of 1.6%, 9.6% and 20.9% had no significant difference compared with the control group（P＞0.05）. After cryopreservation, the contents of soluble sugar and total protein in S. hexandrum seeds with four kinds of water content increased, and the content of soluble sugar was the biggest, while the content of starch in seeds showed a downward trend as a whole, and the activities of superoxide dismutase and peroxidase declined slightly when the water content was 1.6% and 9.6%. The content of MDA increased when the water content was 1.6% and 30.5%, but decreased when the water content was 9.6% and 20.9%, indicating that the seeds with different water content were damaged to different degrees after freezing in liquid nitrogen.The activities of antioxidant enzymes decreased, while the increase of protein content and the accumulation of soluble sugar content caused by starch degradation improved the low temperature tolerance of seeds. As a result, the content of malondialdehyde（MDA） in chilling injury products showed different trends. The seeds of vitrification freezing group with 1.6% water content and seeds of direct freezing group and slow freezing group with 9.6% water content were the top three places by entropy weight TOPSIS. The results showed that the liquid nitrogen cryopreservation technology of S. hexandrum seeds could be feasible, and the seeds with 9.6% water content would be the best cryopreservation conditions by direct freezing or slow freezing.