In the present study the ameliorating effects of Si nutrition supplied as 1 mmol L⁻¹ sodium silicate were proved on the seedling growth of canola (Brassica napus L.) seedlings under salinity stress (i.e. 0, 30, 60, 90 and 120 mmol L⁻¹sodium chloride). Salinity obviously disrupted cellular homeostasis, something was evident in the decreased percent of scavenging HO^-free radical and Metal chelating %, and hence reduction in photosynthetic pigments contents (chl.a and carotenoids). Silicon nutrition, however, enabled canola cells to balance between the steady-state levels of different ROS through improving the detoxification of the excess ROS. This was prevalent in higher scavenging percent of HO^- and metal chelating. In addition, Si maintained membranes integrity through improved levels of lipid peroxidation inhibition %. Si buffered oxidative stress through sustaining the enzymatic and non-enzymatic scavenging capacity of reactive oxygen species in salt-stressed plants. Enzymatic antioxidants such as (CAT, SOD, APX, and POS) activities as well as non-enzymatic antioxidants such as carotenoids contents phenolics contents increased at 120 mmol L⁻¹ sodium chloride. Thus, silicon nutrition alleviated the deleterious effects of salinity on the growth of canola plants through increased reactive oxygen species scavenging capacity (enzymatically and non-enzymatically), maintaining the membrane integrity of seedling cells as evidenced by raising the reducing power contents, sustained higher levels of chlorophyll. Consequently, enhance seedlings growth observations.