Abstract: The efficient petroleum hydrocarbon degrading bacteria were isolated and screened from the polluted soil of an abandoned chemical plant in Lianyungang City. The physiological and biochemical characteristics of the strains were studied, sequenced and identified. The related environmental factors of diesel fuel degradation were analyzed by single factor test. The results showed that four strains of diesel degrading bacteria were isolated from polluted soil. After sequencing and homology comparison, the highest homology with the four strains were Enterobacter_cloacae (HY1), Achromobacter_pulmonis (HY2), Pseudomonas_taiwanensis (HY3), Pseudomonas_aeruginosa (HY4), and the homology was more than 98%. The four strains had different abilities of producing surfactant and degrading diesel oil. HY1 and HY2 had the highest degradation rate of diesel oil. When the diesel oil concentration was 0.5% and the treatment time was 20 days, the degradation rate of diesel oil by the two strains was more than 37%. After optimizing the degradation conditions by single factor experiment, when the diesel oil concentration was 0.5% and the degradation time was 8 days, the optimal degradation conditions of HY2 and HY1 were initial pH 7, shaking table speed 180 r/min and inoculation amount 3%-4%. At this time, the degradation rates of diesel oil by the two strains were 40.15% and 43.87%, respectively. This study can enrich the strain information of petroleum hydrocarbon degrading bacteria and provide strain resources and data support for the remediation of petroleum hydrocarbon contaminated soil.