According to the characteristics of oil contaminated wastewater, four strains of microorganism, named TA-11, TA-17, HA-9, HD-1, which can degrade oil and CODCr of oil contaminated wastewater were picked out from the oil contaminated soil and activated sludge of Panjin pitch plant wastewater treatment system. The research results showed four strains of microorganism can all remove oil and CODCr. in oil contaminated wastewater effectively, the highest removal ratio of CODCr after 64 hours was 68% at the pH 7.0 and the temperature of 30 degree Celsius, The removal ratio of CODCr in oil contaminated wastewater of mixed bacilli was much higher than that of unitary bacilli.