Purpose The purpose of this study was to investigate the effects of knee reinforcement training using neuromuscular electrical stimulation(NMES) therapy on range of motion, strength and gait in patients with total knee arthroplasty. Methods Subjects (n=24) were recruited and randomly assigned to study group (n=12) and control group (n=12). The intervention of the study group was conducted with knee extensor active exercise program combined with NMES applied to knee muscles for 30minutes, 5 times a week, for 2 weeks. Control group conducted intervention with same time and frequency as the study group while applying pain control electrical stimulation. Outcome measures include Numerical Rating Scale(NRS), Range of motion(ROM) and muscle strength of knee joint, and gait ability. Results After intervention, the significant changes were seen in NRS(p<.01), knee flexion angle(p<.01), and muscle strength(p<.01) for both groups, but there were no significant differences in NRS and muscle strength outcome between groups other than flexion angle(p<.05). In outcome measure for gait ability, significant changes were seen in gait speed(p<.01), step length, stride length(p<.01) and cadence(p<.05) after intervention in both groups. Significant differences in outcome between two groups were found in speed(p<.01), step length(p<.05) and stride length(p<.05). Conclusion knee extensor strengthening combined with NMES could improve pain, knee joint function and gait ability in patient with total knee Arthroplasty.