This study investigates the effects of cadmium (Cd) stress on the morphological and physiological characteristics of maize seedlings. Five maize inbred lines (Kui3, CML118, Mo17, B73, and B77) were exposed to five Cd concentrations (0, 1, 3, 5, and 7 mg L⁻¹) for 15 days. Cd stress significantly reduced biomass, leaf area, and relative water content in all lines, with the most severe effects observed at higher Cd concentrations. Leaf SPAD values also decreased, indicating reduced chlorophyll content. Cd stress increased the activities of antioxidant enzymes such as SOD, POD, and CAT, leading to enhanced membrane lipid peroxidation. The Cd content in the roots was higher than in the shoots, with Mo17 showing the highest transfer coefficient (0.33–0.83) and B73 the lowest (0.06–0.44). Kui3 exhibited the greatest decrease in soluble protein content, while B73 showed the lowest increase in proline content, indicating higher Cd tolerance. Soluble sugar content decreased under Cd stress, but increased in some lines. The study highlights significant genotypic differences in Cd stress response, providing insights into the mechanisms of Cd tolerance in maize inbred lines. These findings contribute to understanding the physiological responses of maize seedlings to Cd stress and support the development of Cd-resistant varieties for safe crop production.This study investigates the effects of cadmium (Cd) stress on the morphological and physiological characteristics of maize seedlings. Five maize inbred lines (Kui3, CML118, Mo17, B73, and B77) were exposed to five Cd concentrations (0, 1, 3, 5, and 7 mg L⁻¹) for 15 days. Cd stress significantly reduced biomass, leaf area, and relative water content in all lines, with the most severe effects observed at higher Cd concentrations. Leaf SPAD values also decreased, indicating reduced chlorophyll content. Cd stress increased the activities of antioxidant enzymes such as SOD, POD, and CAT, leading to enhanced membrane lipid peroxidation. The Cd content in the roots was higher than in the shoots, with Mo17 showing the highest transfer coefficient (0.33–0.83) and B73 the lowest (0.06–0.44). Kui3 exhibited the greatest decrease in soluble protein content, while B73 showed the lowest increase in proline content, indicating higher Cd tolerance. Soluble sugar content decreased under Cd stress, but increased in some lines. The study highlights significant genotypic differences in Cd stress response, providing insights into the mechanisms of Cd tolerance in maize inbred lines. These findings contribute to understanding the physiological responses of maize seedlings to Cd stress and support the development of Cd-resistant varieties for safe crop production.