On the basis of ascertaining the dominant and recessive relationship and separation ratio of quality traits such as leaf type and peel stripes, the separation of dominant and recessive traits was studied to infer whether the genes of the previous generation were homozygous. Individuals with homozygous recessive traits can be confirmed in F2 generation, and homozygous single lines with dominant traits can be confirmed in F3 generation, which speeds up the breeding process of watermelon inbred lines.