In this study, joint moments, support moments and lumbar lordosis were investigated for two different symmetrical lifting techniques using the three-dimensional motion analysis: squat and stoop. Thirteen male volunteers lifted boxes weighing 5, 10 and 15kg by both squat and stoop lifting techniques. There were no significant differences in maximum lumbar joint moments between two techniques. And the extension moments of hip and ankle joints contributed the most to support the body in squat lifting, and the knee flexion moment played an important role in stoop lifting. There were individual differences in lower extremity joint moments when the lumbar lordotic curve appeared. However, the correlations about angles and moments between lumbar and lower extremity joints could confirm the results from the support moment analysis. In conclusion, lower limbs contribute to minimize mechanical stress on the waist by the change of lordotic curvature in the lumbar spine for the safe lifting technique.