Abstract: In order to investigate the removal efficiency and remediation characteristics of petroleum hydrocarbons in the oligotrophic and low organic matter soil in the northern of Shaanxi oilfield area, the remediation of petroleum-contaminated soil was studied by bioaugmentation and biostimulation, respectively. The removal efficiency of petroleum hydrocarbons, and the changes of soil microbial community compositions were determined by instrumental analysis and molecular biological technique, respectively. The results showed that biostimulation with nutrients was more effective for petroleum removal than that of bioaugmentation with degrading flora. When soil moisture was adjusted to 15.1% by adding sterile water, and the soil C/N ratio was adjusted to 100:20 by adding KNO₃ to the soil, the removal efficiency of petroleum hydrocarbon was 44.77%; while the petroleum removal efficiency was 17.87% when the soil was bioaugmented with petroleum-degrading flora. Under the conditions of 5.1% and 15.1% moisture content, the bioaugmented degrading flora could survive and growth well, but the survival and growth of the bioaugmented flora did not improve the petroleum biodegradation. The nutrients and soil moisture contents were the abiotic factors, while the uniformity and abundance of microbial communities were the biotic factors that influenced petroleum hydrocarbon degradation in the polluted soil. Our study indicated that the suitable remediation methods for local climate conditions should be considered in order to improve the diversity and activity of soil microorganisms.