To evaluate maize hybrids response to salinity stress, a factorial experiment was performed with three replications at the Ardabil Agricultural and Natural Resources Research and Education Center during 2020. The first factors were six maize hybrids (SC647, TWC647, SC704, SC705, SC706 and SC715), and the second factors were three levels of salinity stress (0, 100 and 200 mM NaCl). Electrophoretic analyses by using 8% slab polyacrylamide gels indicated that three, two and one isoforms for superoxide dismutase (SOD), peroxidase (POX) and catalase (CAT) were observed, respectively, and for each isoform band the “density × area” scores onto gels were evaluated by MCID software as enzymatic activity. The applied salt stress reduced dry weight seedlings, but increased malondialdehyde (MDA), peroxide hydrogen (H₂O₂), and activity of SOD, POX and CAT isoforms. Significant correlations were observed between seedling dry weight and POX and CAT. The cluster analysis based Ward method was classified maize hybrids in two different groups. TWC647 hybrid with high biomass, high oxidative defense system and low MDA was salt-tolerance. The results indicated that salt-tolerance hybrids, which are associated with enhanced oxidative defense system.