Genetic diversity of 41 pummelo (Citrus grandis Osbeck) germplasms and 5 relative species collected from Hunan province were identified and evaluated using the markers from sequence related amplified polymorphism (SRAP). The results showed that the average number of 16.6 alleles could be amplified out from every primer combination, and total of 283 alleles were detected from 17 SRAP markers, 235 out of which presented polymorphic, accounted for 83.0%. Gene diversity value changed from 0.431 7 to 0.770 0 with an average of 0.544 3 for each primer, which showed a high level of genetic diversity among the analyzed germplasms. 37 specific SRAP polymorphic bands were scored, and 42 genotypes from the 46 germplasms were completely identified by SRAP markers. The mean number of alleles per locus (A), percentage of polymorphic loci (P) and direct count heterozygosity (H0) of the genotypes from the pummelo germplasms and their relative species were 9.02, 67.77% and 0.343, respectively. 41 pummelo germplasms and 5 relatives could be clustered into 6 groups with the similarity coefficient of 0.792 by the method of UPGMA. Group 1 and group 2 were respectively composed of 24 and 11 pummelo varieties, group 3 was hybrid pummelos, group 4 was two of hybrid pummelos and two relatives, group 5 included two relatives of seedless red peel orange and Satsuma mandarin, and group 6 was only limon (Citrus limon (L.) Burm f.). Parental origin of the hybrid pummelos were discussed in the paper as well.