Abstract：In this study, RAPD analysis was applied to assess the genetic diversities and relationship with 47 internal and external summer squash（Cucurbita pepo L.）germplasm resources. Genomic DNA of 47 summer squash germplasm resources was amplified by RAPD. 30 polymorphic primers screened out of 520 random primers were used and 367 reproducible bands were produced. Among them, 302 bands（82.29 %）were polymorphic. The genetic diversity of summer squash germplasm resources was very rich. This result is consistent with morphological study. The cluster analysis divided the germplasm resources used in this study into 2 groups. The first group was divided into 4 sub-groups. The second group was divided into 5 sub-groups. The different sub-groups of summer squash had their own phenotype characteristics. For growth habit, the genetic relationship between dwarf and half-vine was the nearest. For skin color, the genetic relationship between white and green was the nearest. And the genetic relationship was the farthest between white and colored.