Abstract:The analysis of variation at the molecular level has been proven extremely useful in the reconstruction of plant phylogenetic relationships. A DNA fragment of 3100-base pairs (bp) in the chloroplast genes ndhF and psbA has been amplified from 9 species of 7 genera in the subtribe Astragalinae and 1 species in the subtribe Glycyrrhizinae. A proper procedure for specifically PCR-amplifing the 3.1 kb fragment was presented. By this procedure, the PCR products could be digested directly after amplification. The restriction fragment length polymorphism (RFLP) analysis of the PCR-amplified products indicated that it had potential systematic significances in the phylogenetic studies of the subtribe Astragalinae. This approach could also reduce time, expense and the amount of DNA required, and furthermore, obtain reliable results.