Objective To investigate the clinical efficacy and safety of low-intensity electrical stimulation of the auricular vagus nerve in treatment of primary coronary microvascular angina. Methods A total of 130 eligible patients with primary coronary microvascular angina, who were admitted to Mianyang Central Hospital from June 2018 to September 2020, were enrolled and divided into study group and control group using a random number table, with 65 patients in each group. The patients in the study group received electrical stimulation of the auricular vagus nerve combined with nicorandil, while those in the control group received nicorandil alone, and the course of treatment was 12 weeks for both groups. The two groups were compared in terms of the changes in angina symptoms, Seattle Angina Questionnaire (SAQ) score, and exercise tolerance (including the total time of Treadmill exercise and the time from start of exercise to 0.1 mV depression of ST segment) after treatment, and adverse reactions were observed for both groups. Results There was no significant difference in the incidence rate of adverse reactions during treatment between the two groups (P>0.05), and compared with the control group, the study group had a significantly shorter duration of anginal attack and significantly lower frequency and degree of pain of angina attack (P<0.05). Compared with the control group after 12 weeks of treatment, the study group had a significantly higher SAQ score (P<0.05) and significantly longer total time of Treadmill exercise and time from start of exercise to 0.1 mV depression of ST segment (P<0.05). Conclusion Low-intensity electrical stimulation of the auricular vagus nerve can improve exercise tolerance, clinical symptoms, and quality of life in patients with primary coronary microvascular angina, with little adverse effect.