Creating mutants is an effective way of germplasm innovation and useful basis of functional genomics research in Chinese Cabbage. In this study, the inbred line ‘A03’ of Chinese cabbage was selected as wild genotype for constructing one mutant library because of its self-compatibility and easy microspore culture. The influences of EMS treatments on vigor of M1 and M2 seeds and seedlings were investigated. The variations in phenotypic traits of M2 population at heading stage, harvest stage and reproductive growth stage were further investigated. The results showed that the more suitable mutant scheme of creating mutants was considered to soaking seeds with EMS 0.4% and with time 16 h. The way of continuous treatments with EMS on seeds of two generations could be used in constructing mutant library of Chinese cabbage. Within the obtained mutant population, there was wide variation in phenotypic traits of M2 individuals at heading stage, harvest stage and reproductive growth stage, with mutation frequencies of 21.65%, 22.40% and 25.65%, respectively.