In present paper, an atmospheric-pressure low-temperature plasma treatment of pyrolysis fuel oil (PFO) was investigated in dielectric barrier discharge plasma torch reactor. The effect of the applied voltage and the volume of feedstock, as the main parameters, on the cracking of PFO were studied. By increasing the applied voltage from 10 to 16 kV, the production rate of hydrocarbons containing methane, ethylene, acetylene, propane, propylene, and C-4 rise 18 times. In this case, the production rate of hydrogen increases by approximately 14 times and reaches 7.27 x 10(-3) mol/min for 16 kV. In the feedstock volume investigation, based on limitation of reactor volume, the production rate of hydrocarbons decreased from 0.44 x 10(-3) to 0.15 x 10(-3) mol/min by increasing volume of feedstock from 1 to 5 cc.