Abstract: 【OBJECTIVE】Genetic relationships and classifications of a set of watermelon accessions were analyzed to provide the experimental support for utilizing effectively genetic materials for variety development.【METHOD】SRAP technique was adopted to analyze 64 watermelon accessions；【RESULTS】fifty-one primer combinations with clear band pattern and polymorphism were selected from over 700 primer combinations, These primer combinations produced 431 bands in which there were 243 polymorphic bands and the average frequency of the polymorphisms is 56.4%. When the wild-type material No.57 was removed, the frequency of the polymorphisms of other materials is 39.4%.The genetic similarity coefficient of the 64 accessions were calculated by the NTSYS software using 243 polymorphism SRAP bands. It’s ranged between 0.47 - 0.97. When excluding most variable four accessions including No.57, and range decreased to 0.87-0.97；【CONCLUSION】It showed that the watermelon has a limited genetic differentiation among the breeding lines and broaden genetic diversity is very important for watermelon breeding