Seeds of the melon strain ‘3-2-2’ were treated by ethyl methane sulfonate (EMS) with 8 different concentrations and 4 different time in this study, and the suitable EMS mutation dosage for seed mutagenesis was determined as a concentration of 1.2% and 24 h by studying the germination rate of M1 plants. By this way, the melon mutant library containing 67 M1 families and their selfing seeds of M2 was constructed. For M1 individuals in the mutant library, phenotypic traits of 541 seedlings at whole growing period were investigated, resulting in total mutant frequency of 71.53%. For M2 individuals in the mutant library, length of internode, diameter of main stem, length of leaf, width of leaf, length of petiole and diameter of petiole of 603 seedlings were investigated: in addition to length of internode, differences of the other 5 traits were significant compared to the wild type; variation coefficient of different phenotypic traits were different, the maximum was 15.37% in length of petiole, and the minimum was 7.10% in length of internode; in M2 generation, leaf color of No.25 line appeared in segregation of yellow and green.