Abstract: Driving mechanism of microbial-flooding,a new ly developed tertiary recovery technology in recent years,is that the biosurfactants,organic solvents and gases pro-duced during underground fermentation of mi crobe in-crease oil layer pressure,emulsify crude oil,lower crude vis cosity and improve permeability,thus in crease pro-duction and enhance oil recovery.Experiment and appli-cation of this technology in well group of Chai19in Wangji oilfield showed that it is suitable for use in Henan oilfield and that oil driving effects are relatively good in areas with low water content but high wax and gel contents.