Genetic diversity of 30 japonica rice varieties, which were bred by Jiangsu Province or introduced from Japan, was analyzed by 64 SSR primers covered on 12 rice chromosomes. The results indicated that a total of 50 SSR primers performed polymorphism and 140 alleles loci were detected. The average number of alleles per SSR locus was 2.8 with a range from 2 to 5. The effective alleles were 94.336 with average 1.887. The value of allelic polymorphism information content (PIC) ranged from 0.064 to 0.752, on an average of 0.410 per SSR marker. The genetic similarity of paired varieties ranged from 0.386~0.956 with average 0.719, and the genetic similarity of 81.4％ tested materials ranged from 0.600 to 0.800．The results of UPGMA indicated that the 30 rice varieties could be clustered into three groups．Based on the pedigree analysis, it was concluded that the rice varieties in Jiangsu Province had closer genetic relationship with each other and the genetic diversity was not enough at present. It is necessary to explore the genetic resources and enlarge the genetic background in order to increase the yield in current rice breeding.