In this study, degradation of phenol by electron beam irradiation in aqueous laboratory solutions and also in a wastewater of steel industry has been investigated. The standard solutions of phenol in the range of 5-22 kGy underwent electron irradiation and their concentrations before and after the exposure were measured using UV-Vis spectrophotometer at 460 nm. The concentration of phenol in the effluent before and after irradiation at 10 kGy was measured by GC/MS analysis. The effect of experimental parameters like absorbed dose and initial concentration on the efficiency removal was studied. According to the observations, with increasing absorbed doses the removal percentage increases and also in a constant dose by increasing the concentration the amount of removal gradually decreases. In the optimum dose,10 kGy, the removal percentages of phenol in the standard solution with concentration of 10 mg/L and in the wastewater of steel industry were 93.5% and 41%, respectively.