Disclosed herein are novel microorganisms having excellent biodegradability and a method for the bioremediation of oil-contaminated soil. The novel microorganisms are specified as Rhodococcus baikoneurensis EN3 KCTC19082, Acinetobacter johnsonii EN67 KCTC12360 and Acinetobacter haemolyticus EN96 KCTC12361. In the bioremediation method, in addition to said novel microorganisms, various microorganisms of Nocardia sp., Gordonia sp., Rhodococcus sp. and Acinetobactor sp. can be used, and the oil biodegradation activities of these microbial strains can be increased by adding biosurfactant 2-alkyl-3-hydroxylic acid or its derivative. According to the disclosed invention, oil-contaminated soils can be purified in an effective, economical and eco-friendly manner compared to prior bioremediation methods.