Abstract: This research has set up the bacteria genetic expansion and RFLP (Restriction Fragment Length Polymorphism) technique. It focuses on the some practical problems about MEOR (Microbe Enhanced Oil Recovery) in Jilin Oil field. These problems include the effect of trial, the reason of success and failure, the microorganism’s adaptability in oil deposit and applied latent capacity in the field. In order to investigate the genus, concentration, competition ability and developing oil capacity of the bacteria. The research offers effective technology means and basis for the detection and evaluation of the commerce bacteria. This text has summed up the characteristic, function and basic principle of PCR (Polymerase Chain Reaction) technology, the theory, the step and method of the bacteria genetic detection. It explained the main technique factors which affected and conditioned the steps of the field trial. By way of systems analysis and following application for the aim microbe, and explained the major technology factor of each link of restriction field. For this technology of adjustment and optimizes tentative design and confidence to test the course, and provided the reliable basis.