Pollution of oil hydrocarbons in the soil is one of the environmental problems. These materials change the physical, chemical and biological properties of the soil and ultimately affect the fertility. Therefore, in order to investigate the effect of oil pollution on the stability of the soil structure, a factorial experiment was conducted in a completely randomized design with three replications in the greenhouse of the College of Agriculture, Isfahan University of Technology. Soil contaminated with oil was brought from a contaminated site of Masjed Soleiman in Khuzestan province. Three-liter pots were used for the experiment. Experimental treatments consisted of three levels of contamination (0, 4, 8% by weight), two types of bagasse and three species (0, 5 and 10 tons per hectare) and cultivated and uncultivated pots. To assess the stability of the soil structure, wet sieving, clay dispersion and soil moisture characteristics (HEMC) methods were used, and weighted average diameter of aggregate (MWD), geometric mean of aggregate diameter (GMD), percentage of water stable aggregates (WSA), dispersible clay content (DC), stability indexes for rapid and slow wetting (SIfast and SIslow), structural stability index ratio (SR) and drainagable pore size ratio (VDPR) were calculated. The results showed a positive effect of oil pollution on the MWD and GMD, and reducing effects on the drainage pore volume ratio and stability index of the rapid and slow wetting procedure. Petroleum hydrocarbons increased the organic carbon of the soil and created an under the critical level of water-repellency. A positive correlation was found between the water repellency index (R), the soil- water contact angle (?), MWD, GMD and WSA with organic carbon and the percentage of total hydrocarbons. The effect of bagas and planting on MWD, WSA, DC, VDPR, SIfast and SIslow was statistically significant. Oil contamination increased the stability of the soil structure by causing by the under the critical level of water-repellency. But oil, due to increasing the amount of toxic elements and compounds that is absorbed by the plant, produces adverse conditions for growth and vegetation. Promoter materials like bagas, by improving soil properties and stimulation of the microorganisms reduce the concentration of hydrocarbons and its destructive effects on the plant and thus increasing phytoremediation effects. Keywords: Oil pollution , Biochar, Soil structure stability, High energy characteristic curve, Masjed Soleyman city