A method for RT-PCR amplifying long fragments cDNA was established and the 7.4 kb full-length cDNA of Hepatitis A virus(HAV) H₂ strain was amplifyed by reverse transcription and polymerase chain reaction (RT-PCR).HAV H₂ was precipitated by anti-H₂ serum specifically, then the RNA of HAV H₂ was isolated from this precipitation by acid guanidinium hydrochloride-phenal-chloroform extraction. The first-strand of HAV H₂ cDNA was synthesised by reverse transcriptase without RNase H activity,then was ampliflied by PCR using the 32mer primer and the Taq DNA polymerase with Deep Vent DNA polymerase. For obtaining longer PCR products,it is necessary to prepare high quality RNA and employ the longer primers and special Taq DNA polymerase.