The genetic diversity and Relationships among 45 orchardgrass accessions was tested by SRAP. Twenty-one primer combinations were used and 438 bands were produced in SRAP, of which 363(82.08%) were polymorphic. The coefficient range of genetic similarity was 0.6248-0.966 with 0.7958 on average, which showed rich genetic diversity of orchardgrass germplasm, too. 45 accessions could be divided into 4 main groups by cluster and principal component analysis, which not only revealed the geographical distribution of accessions but also reflected the difference of karyotype. The result suggested that the genetic diversity of orchardgrass were correlative with karyotype and geographical distribution of accessions. In addition, the narrow genetic basic of Chinese orchardgrass cultivars were found. Overall, it is efficient to breed more excellent orchardgrass and release the genetic variation among accessions by this research.