As viral vaccines sometimes induce the side effects which intimidate humans, it is urgently required to study about the side effects of viral vaccines. Most vaccines are derived from the biological forms. Hence it should be established the efficient and sensitive evaluation methods for the possibility of dangerous contaminants such as viruses and the stability of vaccines. A lots of vaccine products have been imported, or in sale or being developed in nation. Some of products may be mixed with the hazardous viruses derived from animal or human resources. Such hazardous viruses should be identified specifically and efficiently. Biological products are not permitted to distribute or obtain without presenting the result of absence experiment of hazardous viruses and prion and the validation data of inactivation experiment during processes. In order to detect viruses, there were TEM for viral particles, infectivity assays and detection methods for nucleic acids. However, these methods have defects such as insensitivity and inaccuracy. It should be considered to detect only the hazardous viruses with specificity, precision and accuracy during the processes of preparation, transportation and storage. It is noted to increase the detection limit in order to detect the minute hazardous factors during preparation processes for viral vaccines. This study is focused on the establishment of various sensitive PCR/ELISA methods for HBV virus which enhance the detection limit in order to detect the minute hazardous factors during preparation processes for viral vaccines.