Abstract: DNA immunization can induce humoral and cellular immune responses to against a range of viral pathogens.The results show HCV core and HBV preS2S can induce strong immune responses in DNA immunization.After muscular adminstration was performed,pc154S2S plasmid DNA was detected initially in all highly vascularized tissues.Two days latter,they mainly stayed at span,blood and injceted muscles;Seven days latter,the pc154S2S only can be found in the injected muscles,it can be kept for nine weeks.Intramuscular injections of plasmid has no clinical symptom and histopathogical damages in the injection sites.