In order to study the effect of isokinetic muscle strength training on upper limb motor function of stroke hemiplegic patients, 50 stroke hemiplegic patients hospitalized in a hospital from May 2017 to May 2018 were randomly divided into observation group and control group, with 25 cases in each group. The control group received routine rehabilitation training and clinical drug treatment. The rehabilitation training mainly included exercise therapy, occupational therapy and physical factor therapy. The treatment lasted for 8 weeks, 5 days a week and 2 times a day. The observation group received isokinetic muscle strength training besides the control group. The upper limb function was evaluated by FMA, ARAT, shoulder abduction, wrist dorsiflexion, and EMG integral. The BI index and DASH scale were used to evaluate the life aspect. The muscle strength was evaluated by four mechanical indexes: peak moment, peak moment weight ratio, average power and total work. Comparing the indexes of upper limb motor function recovery, life score and mechanics between the observation group and the control group before and after treatment. The results show that the indexes of the observation group after treatment were greatly improved compared with those of the control group and before treatment. It can be seen that isokinetic muscle strength training can improve the joint flexion and extensor strength of stroke patients with hemiplegia, promote the improvement of upper-style motor function of stroke patients with hemiplegia, and help patients strengthen their self-care ability.