: The paper introduces a new anti-virus idea of Software Vaccine technique. It can apply the security technique inside the software itself. By inserting the software vaccine into the application software and reconstructing it, we can make the application software have immune ability from malicious attack. Besides, it can also help to find and trace the new viruses and their makers in very early stage. In this paper we will introduce the principle of software vaccine technique, give some samples of encryption algorithms to be used in software vaccine technique, and describe its application in early virus finding and tracing. We believe that the software vaccine technique will be a powerful anti-virus weapon to catch those virus makers. Keyword: Software vaccine, anti-virus, virus finding and tracing, encryption algorithm.