The aim of the present study was to examine whether mental practice (MP) in conjunction with repetitive transcranial magnetic stimulation (rTMS) can improve the upper limb function of sub-acute stroke patients. This study was conducted with 32 subjects who were diagnosed with hemiparesis by stroke. The experimental group consisted of 16 members upon each of whom was performed MP in conjunction with rTMS, whreas the control group consisted of 16 members upon each of whom was performed MP and sham rTMS. Both groups received traditional physical therapy for 30 minutes a day, 5 days a week, for 6 weeks; additionally, they received mental practice for 15 minutes a day. The experimental group was instructed to perform rTMS, and the control group was instructed to apply sham rTMS for 15 minutes. A motor cortex excitability analysis was performed by motor evoked potentials (MEPs), and upper limb function was evaluated by Fugl-Meyer Assessment (FMA) and the Box and Block test (BBT). Results showed that the amplitude, latency, FMA, and BBT of the experimental group and the latency, FMA, and BBT of the control group were significantly improved after the experiment (p<0.05). Significant differences were found between the groups in amplitude and latency after the experiment (p<0.05). The results showed that MP in conjunction with rTMS is more effective in improving upper limb function than MP alone.