Objective: To investigate the effects of different doses of aerobic exercise on the microvascular function of habitually sedentary college students. Methods: A total of 69 students from Hubei Minzu University were recruited and divided into sports group A, sports group B and control group, with 23 students in each group (12 boys and 11 girls). The exercise group received 12 weeks of aerobic exercise intervention, in which group A exercised 1-2 times a week, group B exercised≥3 times a week, and the control group did not carry out any systematic sports. Microvascular response, Transcutaneous partial pressure of oxygen(TcpO 2), Nitric oxide, Nitric oxide synthase (NOS) and En dothelin-1 (ET-1) were measured before and after the test. Results: After the test, the microvascular reactivity showed group and time interaction( P <0.01), in which exercise group B was greater than that of control group and exercise group A ( P <0.01). There was no significant difference between exercise group A and control group ( P >0.05), but the percutaneous partial pressure of oxygen ( P =0.53) had no time interaction with other groups; NO( F =6.32) and NOS( F =7.91) had group and time interaction, in which exercise group B was greater than control group and exercise group A ( P <0.01), and there was no significant difference between exercise group A and control group ( P >0.05). Conclusion There is a "dose effect" relationship between aerobic exercise and microcirculatory blood perfusion and endogenous NO. Continuous aerobic exercise ≥3 times a week for 12 weeks improved microcirculatory blood perfusion and promoted endogenous NO production in sedentary college students, but doing aerobic exercise for 1-2 times a week had no significant effect on microcirculatory blood perfusion and endogenous NO.