In this study, the inbred line ‘6421’ was selected and treated with different concentrations of mutagen (ethyl methane sulfonate(EMS)) to study the effect of EMS treatments on seeds germination and some biochemical characteristics of seedlings, to construct mutant library and analyze the phenotypic traits. The results showed that treated with 1.0% EMS, the germination rate and seedling survival rate were 41.01% and 49.32%, respectively, which were close to those with LD50, the seedlings had the highest enzyme activities of SOD (246.45 U/g), POD (33.99 U/g) and CAT (158.10 U/(g?min)), and the MDA content of seedlings was 1.85 times as much as the control. 562 mutant lines were identified and classified into five categories: leaf, stem, fruit, fertility and growth period mutations, which were accounting for 12.73%, 21.56%, 6.92%, 45.33% and 13.46% of the total mutation respectively.