The present paper studies effect of maximal exercise and submaximal exercise on treating type 2 DM (diabetes mellitus). In type 2 DM, pancreas does not produce enough insulin or body cells do not respond to the produced insulin. As a result, level of blood sugar increases. Approximately, 90 percent of diabetes are related to type 2 DM. In this research, statistical population is made up of 10 male volunteers whose mean age varies from 24 to 69, height is equal to 171.7∓ 6.12 centimeters, weight is equal to 81.52 ∓ 1.59 kilograms, and body mass index( BMI) is equal to 27.65 ∓ 1.88 . The volunteers participated in two sessions of aerobic exercise including 30 minutes of fast running, one session with speed equal to 70 percent of heart beat and another session with speed equal to 100 percent of heart beat. Data analysis was done based on descriptive and inferential methods. Moreover, statistical measures such as measure of central tendency, measure of dispersion were used to study findings and paired T test and Mann Whitney U- test were used to compare relation between data dependent variables in constant and non- constant groups at confidence level equal to 95 percent. Results of paired T test shows that doing maximal and submaximal exercises affects BMI and percent of glycosylated hemoglobin.