The purpose of this study is to see how the sling lumbar stabilization exercise affects muscle body type and subjective pain degree of 17 middle-age men who are diagnosed with sacroiliac joint syndrome and investigate the effectiveness. The subjects of this study are patients who have been diagnosed with sacroiliac joint syndrome through tests like X-ray in S Orthopedics in C City and have had chronic lumbar pain for more than 6 months and the before and after results about subjective pain degree through three dimension Moire Muscle Body Type Tester and subjective pain degree through VAS Pain Awareness after sling lumbar stabilization exercise 3 times a week, 30 minutes a time, total 24 times for 8 weeks have revealed the following: The change of muscle body type has been comprehensively improved in the statistics before and after the exercise and the subjective pain degree has also comprehensively decreased in the statistics. Therefore, sling lumbar stabilization exercise is proved to give positive affect to muscle body type and pain improvement of the patients with sacroiliac joint syndrome.