To identify and analyze differentially expressed genes between one pair of cells or tissues in different conditions is of great importance in molecular biology study. In recent years, a variety of approaches have been used to identify differentially expressed genes. DDRT-PCR is one of the most widely used approaches. In theory, DDRT-PCR technique is simple. But in practice, some limitations such as high false-positive rate, inhomogeneity of cDNA bands, short cDNA fragments and underrepresentation of low abundance mRNAs exist. Most modifications to DDRT-PCR technique mainly focus on above aspects.