Disclosed herein is a novel recombinant virus vector derived from the attenuated vaccinia virus strain KVAC103. The recombinant virus vector is obtained by inserting an exogenous gene into the KVAC103 and may be used as a safe vaccine delivery vehicle in mammals. Particularly, recombinant viruses obtained by rescuing some of the genes deleted from the parent virus have an enhanced ability to proliferate in cells being cultured, and thus are easily produced. In addition, the recombinant viruses express an increased level of an exogenous antigen, and thus has enhanced immunogenic efficacy. Such recombinant virus vectors may be used in vaccines for preventing diseases, therapeutic vaccines, and molecular biological studies.