Biosurfactants have great advantages in the development of low permeability oil fields and heavy oil fields compared with other synthetic surfactants. The classification of biosurfactants was described. The mechanism of biosurfactant flooding was concluded. The field application methods of biosurfactants in oil fields，including extra situm and underground method were introduced，and the advantages and disadvantages of the two methods were analyzed. The results of the field application of biosurfactants in heavy oil fields and low permeability oil fields was put forward to prove that that biosurfactants have greater advantages in improving the oil displacement effect of oil fields with poor development conditions. At last，the advantages and disavantages of biosurfactants in EOR were summarized and some corresponding suggestions was put forward.