Soil and water resources are a biotic part of the human life. Due Oil contaminated soils with chemicals and dangerous materials endangered environmental human conditions and other living organisms. Therefore, finding the methods to deal with this problem is important. Nowadays many methods have been devised for decontamination of soil, including bioremediation and phytoremediation. these methods have the ability to compete with other purification methods (physical and chemical), with lower costs and less environmental hazards. The Intermediate between normal and engineering reduction of pollutants, includs the use of compost as a bioremediation method for decontamination. Addition of compost to soil is considered as one of the approaches to enhance efficiency of bioremediation of oil contaminated soils which increase nutrients level in the soil and stimulate microbial activities. For this purpose soil of Bakhtiardasht with high petroleum pollution and a long history of contamination was selected, and transferred to the 3 kg pots in the greenhouse of Agricultural of Isfahan University. Biological refining systems were used for three levels of urban waste compost in 0, 2 and 5% w/w ratio of soil. Sterilized compost and soil treatments were selected for a breakdown of microbial soil treatment, and compost in the refining process and soil and the natural compost treatment for the Interactions between microorganisms of soil and compost. Also the effect of different levels of urban solid waste compost on phytoremediation, barley (variety of karoon in kavir), in a factorial experiment in a completely randomized design with three replications were studied at the end of the growth period. At the end of microbial respiration, plant performance and percent reduction of total petroleum hydrocarbons (TPHs), after 45 days also 90 days of incubation was carried out. The highest yield of barley was related to soil and natural compost treatments at the 5 % level of compost. The highest yield that was in reduction of total petroleum hydrocarbons related to 5% of soil + natural compost treatments with barley after the 90 days that a contamination rate of hydrocarbon decreased from 35000 to 16100 mg/kg (54% reduction) and 38% reduction for the treatment independent of the plant. However, reducing of pollution in the same treatment of the independent plants was about 23% during 45 days incubation. This indicates the role of plants in the refining process was effective. The results showed that adding 2 and 5% w/w of compost to the soil, increased microbial respiratio up to 36/8 and 45/6 (mg co 2 /kg soil) respectively, There wa significant difference in respiration rate between zero level of compost and other two levels (2% and 5%) from the beginning of incubation. The highest percentage of carbon and organic nitrogen of soil in the same amounts (5% w/w) of urban waste compost observed in treatments of oil+ natural compost, sterile soil+ natural compost, sterile compost+ natural soil, respectively. The results of this study expressed that in general, the addition of nutrients such as compost to the soil can help lant grow (increasing in plant biomass) and removed the soil contaminated. Keywords: Compost, Bioremediation, Phytoremediation, Contamination, Treatment.