A psychrotrophic petroleum-degrading bacterium Pseudoalteromonas sp. P29 was isolated from marine sediment, which was collected during 2nd Chinese Arctic Scientific Expedition. The phenotypic character and biodegradation efficiency on mixed oil or vacuum oil were tested at low temperature. The strain Pseudoalteromonas sp. P29 grew in a range of temperature from 5 to 35A degrees C and the optimum temperature was 25A degrees C. Gas chromatography analysis indicated that the strain might preferentially metabolize shorter-chain alkanes. The biodegradation efficiency were nearly 90 and 80%, respectively, after incubation at 5A degrees C for 28 days in the mineral medium supplement with mixed oil or vacuum oil as the sole carbon and energy source. The results showed a possible exploitation of the strain in future biotechnological processes especially in cold contaminated environments.