Abstract:Modified ISSR-PCR method was presented for isolating microsatellites from non-heading Chinese cabbage (Brassica campestris ssp. chinensis Makino) genomic DNA. The method was carried out through a two-step PCR,and then primers (IP2 and IP3) were designed according to the flanking sequence of microsatellite. The success rate was 12%, which is significantly higher than that of traditional method. The SSR sequence was mainly (GA/CT)n, which was in the majority of 70%. 69 pairs of SSR primers were amplified among eight Brassica types, of which 97% primers had evident amplified bands. The highest amplification rate was 85.5%, occurring in non-heading Chinese cabbage with tetraploid and Brassica oleracea L. And the lowest was 49.3% in Brassica var. botrytis L. of above 69 pairs, 10 pairs were transferable among eight Brassica types, whose amplified fragments were the same,whereas others were diverse in size and number, showing higher polymorphic. Especially in Brassica oleracea L. and Brassica var. botrytis L., which were typical C chromosome types, five loci were tested at most, suggesting these primers developed by ISSR-PCR had rich polymorphic.