Abstract: Through the introduction of biological enzyme technology, the mechanism of oil displacement, the characteristics of biological enzyme and the well selection conditions have been discussed in this paper. After well comparison between pilot testing group and contrast group, the application effect of biological enzyme flooding on enhancing oil recovery has been evaluated. In the pilot testing well group, the injecting pressure of water injection well decreased and the declining rate of connected oil well groups has been controlled. And therefore, the formation pressure has been restored and the recovery of well groups has been increased.