Three strains chosen by enrichment, taming and separation from Jinglou oilfield water were gas production bacteria, hydrocarbon oxidation bacteria and biological surfactant bacterium. After three strains mixed according to inoculation amount in 1:1:1, the biological surfactant in metabolites increased from 1.7% to 2.2%, gas production increased from 95 mL to 120 mL, and pH value decreased from 6.1 to 5.9. The microbial indoor test results for the crude oil of Jinglou oilfield showed that the symbiont digesting strains had a good adaptability, and emulsification of heavy oil viscosity reduction effect was obvious. The drop sticky rate of crude oil could be as high as 63.9%, the viscosity of emulsion oil-in-water varied from 100 to 300 mPa·s, the content of resin and asphalt decreased, and the surface tension of fermented liquid decreased by 9.4%-11.6%. This cold nitrogen microbial production technology was applied in 7 wells of Jinglou oilfield on site with 10-15 m single well radius, 2000-10000 Nm3 nitrogen replacing slug, 2.5-6.0 t microbial fluid. The results showed that the produced liquid per well increased by 1.8-9.8 times, oil production per day increased from 0-0.1 t to a maximum value 2.7 t, oil increment was of 470 t after 115 days, and the effective rate was of 85.7%.