To explore the new method of discriminating Astragali Radix and Hedysari Radix by using PCR amplification of specific alleles, 30 samples of the different Astragali Radix materials and 28 samples of Hedysari Radix were collected. The total DNA of all samples were extracted, trnL-trnF sequence from Astragali Radix and Hedysari Radix was amplified by PCR and sequenced unidirectionally. These sequences were aligned by using Clustul W. Primer was designed and the PCR reaction systems including annealing temperature, dNTP, etc were optimized. All samples were amplified by PCR with specific primer, DNA from Astragali Radix would be amplified 136 bp, whereas PCR products from all of Hedysari Radix were 323 bp. This method can detect 10% of intentional Hedysari Radix DNA into Astragali Radix. PCR amplification of alleles can be used to identify Astragali Radix and Hedysari Radix successfully and is an efficient molecular marker for authentication of Astragali Radix and Hedysari Radix.