The experimental study of in-situ enhanced microbial ecological remediation for oil contaminated loess soil was carried out in oil production areas of North Shaanxi Province. In the experiments, the microbial ecological techniques of in-situ microbial communities combined with the physical and chemical methods as well as soil environment were used for the oil degradation and contaminated soil remediation. The results of the experiment showed that can degradation rate of oil can be up to 40.92% to 80.37% under oil average contents of 2754 mg/kg in the contaminated soil after the in-situ enhanced microbial ecological remediation for 11 to 32 days, which demonstrated the effectiveness of the in-situ microbial ecological remediation methods for oil contaminated soil in northwestern loess region. In addition, it was discussed for feasibility of extend application of the technique.