Background: Poly chlorinated biphenyls (PCBS) are the groups of organicchemical material and toxic, persistent, bio accumulate and pose a risk of causingadverse effects to human health and the environment. PCB compounds arecaused the different health effects in human depending of age, sex, route of entry,intensity and frequency exposure. This study was conducted to determine theeffect of microwave rays, hydrogen peroxide, TiO2 catalyst and ethanol on theDecomposition of PCBS.Methods: In this experiment used a MW oven, Pyrex vessel reactor (250mlvolume), Pyrex tube connector and condensing system. A 900w domestic MWoven with a fixed frequency of 2450 MHZ was used to provide MW irradiation. Raypowers used in 540، 720 and 900w. The PCBS were analyzed by GC-ECDResults: The degradation of total PCBS in terms of 540, 720 and 900W was85.03%, 90.32% and 96.87% respectively. The degradation of total PCBS in termsof ratio to solvent with transformer oil in 1:1، 2:1 and 3:1 was 53.97%، 78.98% and95.13% respectively. The degradation of total PCBs in terms of not using of H2O2/TiO2 and using 20% of H2O2 and 0.05, 0.1, 0.15 and 0.2 g TiO2 was 68.78%,93.97%, 95.13%, 96.18% and 96.87 % respectively.Conclusion: The Microwave thermal reaction was applied for the dechlorinationof PCBs and high efficiencies were obtained. Microwave power and amounts ofreactants added are important factors influencing dechlorination efficiency.