A modified method of 3′-RACE (rapid amplification of 5′- cDNA ends) can rapidly amplify 3′-end of a cDNA only by using a specific primer and Oligo dT.Contrast with the typical 3′-RACE，two-step PCR not only have the advantages of less cost and shorter experimental time ，but can also improve specificity of PCR. This method especially fits for rapid cloning and characterization of the genes encoding the peptides with biological activity.