Plasma jet generated by dielectric barrier discharge system has gain importance in surface modification processes. Characteristics of plasma of the plasma jet depend on type of gas, flow rate of gas, design of electrodes, power and frequency of the power source. In this research, the argon gas is flowed through a hollow tube is investigated. Alternating high voltage power supply connected to electrodes is operated with frequency of 50 Hz. It was found that the lengths of the plasma jet generated by this system ranges from 0.5 cm and 1 cm. The minimum and the maximum electron temperature of the plasma was 0.44 eV and 0.86 eV respectively. The electron temperature increased as the applied voltage was increased. However, the electron temperature decreased when the operating voltage was increased above 6.5 kV to 7.5 kV. It can be explained by the effect of arcing between the electrodes which causes the lost in energy. Also, increasing of the flow rate over a critical limit produces turbulence that also causes reduction in electron temperature of the plasma jet.