Background: This study has conducted an experiment on 14 disabled hemiplegia (female) introduced from D rehabilitation welfare center, sorted out subjects who will enthusiastically and sincerely follow the experiment for 8 weeks (before-after), and grouped them into control group (7 people), and aquatic exercise program group (7 people). After researching the effect of application of exercise program to hemiplegia on physical function and length of lower limb, we have come to the following conclusion. In case of hemiplegia, we have concluded that aquatic exercise program can aid muscle strengthening and lower limb since aquatic exercise program activates physical function and deep muscle, showing a positive influence on muscular strength and flexibility, and a significant influence on balance of lower limb. This result is considered to make people recognize the importance of rehabilitation exercise when making a program for daily life activity, injury prevention, and treatment for hemiplegia, and we believe that such reference will be proposed as a theoretical basis for application of aquatic exercise program to hemiplegia, and further be a great aid to similar studies.