Abstarct: Plasma is an ionized gas consisting of ions, electrons, neutral atoms, radicals and species excited, which is called the fourth element of nature. Today, cold plasma technology can replace many of the most expensive and harmful chemical compounds for the environment and human health for pre-treatment of plant seeds. In order to evaluate the effect of plasma on germination indices and physiological traits of seed and seedlings of rapeseed, a factorial experiment was conducted in a randomized complete block design with three replications in Shahrood University of Technology in 2018. The first factor was the duration of irradiation of canola seeds with cold plasma in six levels: zero (control), 1, 2, 3, 4, and 5 minutes, and the second factor was the voltage applied at three levels of 3, 5 and 7 kV. The results showed that the intensity of active oxygen species and nitrogen production increased with increasing voltage. The results also showed that interaction effects of plasma exposure time and voltage significantly affected malondialdehyde, ascorbate peroxidase, soluble sugar content and root length . Also, the effect of plasma treatment time had a significant effect on seed protein percent. The amount of malondialdehyde was decreased significantly by 35% in plasma treatment for 5 minutes at a voltage of 7 KV compared to control. Also, The amount of ascorbate peroxidase increased significantly by 10% in plasma treatment for 5 min at a voltage of 7 kV compared to control. The percentage of soluble sugar increased significantly by 48% in plasma treatment for 5 min at a voltage of 7 kV compared to control. The percentage of Protein was also increased significantly by 20% in plasma treatment for 4-minute treatment of plasma compared to control. According to the results of this study, the time of five minutes of plasma radiations with a voltage of 7 KV had the greatest effect on most of the studied traits.