Aim To investigate the effect of aerobic exercise on the microvascular rarefaction in spontaneously hypertensive rats (SHR) and explore whether the mechanism is related to the change of vascular endothelial growth factor (VEGF) expression. Methods Male SHR and Wistar-Kyoto rats (WKY), 12 weeks age, were randomly divided into a sedentary group (WKY-SED, SHR-SED), and an exercise group (WKY-EX, SHR-EX). WKY-SED and SHR-SED were used as normotensive control. Exercise groups were subjected to a 12-week treadmill training protocol:20 m/min (about 55%～65% of maximal aerobic velocity), 0% grade, 60 min/day, 5 d/w. Immunohistochemical staining was used to observe distribution and changing of VEGF in rat gastrocnemius muscle of each group. Western blot was applied to examine the expression level of VEGF in rat gastrocnemius muscle. HE staining was used to observe the skeletal mucle capillaries of each group. Results The positive immunoactivity of VEGF in SHR-SED group was significantly lower than WKY-SED group (P<0.01). After 12 weeks, exercise training markedly increased the VEGF expression in rat gastrocnemius muscle (P<0.01). No significant differences were observed in protein expression of VEGF between SHR-SED and WKY-SED (P＞0.05). After 12 weeks, the protein expression in SHR-EX was significantly higher than SHR-SED (P<0.05). Skeletal muscle capillaries were observed by light microscope, the result showed that the capillary/fiber of SHR-SED was significantly lower than WKY-SED (P<0.01). After 12 weeks' training, the capillary/fiber showed an obvious increasing in SHR-EX group. Conclusions Microvascular rarefaction is a possible reason that leads to hypertension. Aerobic exercise can effectively increase the expression of VEGF in the skeletal muscle and accelerate angiogenesis, which may be one of the mechanisms of exercise reversing hypertension.