Aerobic exercise is effective for preventing cerebrovascular diseases. In that, this study focuses on investigating cerebrovascular changes with MRA (Magnetic Resonance Angiography) images by comparing before and after the aerobic activity. As a result, acquired MRA images indicate that signal intensity is increased in case of ECA (External Carotid Artery), STA (Superficial Temporal Artery) with relation to comparing before-after aerobic activities. However, ICA (Internal Carotid Artery), VA (Vertebral Artery), BA (Vertebral Artery) decreased. The comparison of vessel thickness before-after exercising aerobics results in the rise of ECA, STA, while ICA, and VA, BA decreased. Cerebrovascular transformation during aerobic exercises is analyzed with MRA image. Such data show the changes of both blood flow volume and vessel thickness after aerobic activities. As the study demonstrates, aerobic exercises increase cerebral blood flow and vessel thickness. Therefore, aerobic exercises are expected to help preventing cerebrovascular diseases.