[Objective] The aim was to carry out isozyme analysis of jin silver carp (Hypophthalmichthys molitrix Var Jing). [Method] The isozyme of AAT, EST, α-GPD, GPI, IDH, LDH, MDH, ME, PGM and PROT of muscles and liver in two populations of the silver carp (Hypophthalmichthys molitrix): Jin silver carp (a breed through selective breeding) and artificially propagated population bought from Jingzhou city, Hubei Province were examined by horizontal starch gel electrophoresis. [Result] Eighteen loci were observed in two populations. Two loci of GPI* and PGM* in Jing silver carp population and the locus of GPI* in Jingzhou population were polymorphic. The proportions of polymorphic loci (maximum allele frequency≤0.99) of Jing silver carp and Jingzhou populations were 11.11% and 5.56% respectively, expected heterozygosity were 0.015 0 and 0.001 1 respectively. The Nei’s genetic distances were 0.000 59 between two populations. The result of chi-square test of the GPI* gene in two populations showed that their genetic structure has very significant difference. [Conclusion] This study provided a theoretical basis for large-scale extension of Jing silver carp.