This study was performed to explore the effects of walking exercise on blood glucose level in the diabetes mellitus patients. The design of this study was a equivalent pre-post test experiment. The subjects consisted of eighteen diabetes mellitus patients. The walking exercise consists of 22.5minutes, speed of 120walking per minute. Data were analyzed with mean, standard deviation, Wilcoxon signed rank test, Spearman correlation and percentage using SAS program. The results were as follows. 1. The blood glucose level has significantly decreased after walking exercise. 2. Strength of exercise and change of blood glucose level was revealed correlation. 3. Age and strength of exercise was revealed high correlation. 4. Satisfaction after walking exercise was revealed all patients. In conclusion, the walking exercise can decrease blood glucose level. This exercise was show a positive effect on the exercise compliance.