A strain that degrades petroleum hydrocarbon was screened and isolated from oil-contaminated soil of Songyuan oilfield, its colony morphology was observed, and it was identified by 16S rDNA sequence analysis. The results indicated that the colony was white and irregular with rough surface and irregular edge. The 16S rDNA sequence was identified as Pseudomonas pseudoalcaligenes strain. When the temperature was 35℃ and the pH value was 8, the strain had the best degradation effect on petroleum hydrocarbon, and the degradation rate was 75.4%.