Abstract: Microbial enhanced oil recovery (MEOR) offers advantages such as low energy consumption and environmental sustainability. However, its implementation faces significant challenges, primarily the lack of engineered microbial strains capable of surviving and effectively mobilizing oil under extreme reservoir conditions, such as high temperature, high salinity, and anaerobic environments. To address challenges posed by extreme reservoir environments, optimizing the heat tolerance and anaerobic adaptability of microorganisms using gene editing technology is a critical strategy for improving oil recovery efficiency. Using genetic engineering to precisely modify microorganisms isolated from extreme reservoir environments is an effective approach to developing suitable oil recovery strains. This study reviews MEOR technology from three aspects: the mechanisms of microbial oil recovery, its current applications, and future development directions. Additionally, it introduces a new concept, Enzyme Enhanced Oil Recovery (EEOR), which utilizes biocatalysts to alter the physical properties of reservoir rocks, thereby improving oil quality and extraction efficiency. These studies provide valuable insights into the microbial ecosystems of extreme reservoir environments and offer a solid scientific foundation for their practical applications.