Abstract: Twenty-four low-temperature strains were separated from the sludge in a domestic sewage pipeline in winter in Harbin in order to search for a highly effective oil-degrading strain from the natural environment for the treatment of oil wastewater. Eight low-temperature strains which could decompose oil under 5 ℃ were selected by domestication, separation and purification. A low-temperature, highly effective plant oil-degrading strain, 5^#, was isolated by re-screening and was used for further research. The oil degradation rate reached above 70% after strain 5^# was cultivated at a temperature of 5　℃ for five days, under the conditionsof initial peanut oil mass concentration 4，000 mg/L, inoculum size 2%, initial pH 7.2, and rotation speed 120 r/min. Strain 5^# had a 99% similarity with Pseudomonas according to analysis of the 16S rDNA array. Strain 5^#was proven to belong to Pseudomonas genus based on its morphology, biophysiological and biochemical characteristics and the results of the 16S rDNA array analysis.