Abstract: Objective To study the epidemiology of cyclic vomiting syndrome (CVS) in a certain air force unit and analyze its risk factors. Methods The epidemiology of CVS in 5,800 air force servicemen was investigated with questionnaires from September 2008 to March 2009 by random sampling. The epidemiological difference in ground servicemen and air servicemen was compared. Results Of the 4,988 eligible questionnaires, 818 (16.4%) were returned from air servicemen and 4,170 (83.6%) from ground servicemen. The total incidence of gastrointestinal symptoms was 52.3% in air force servicemen, 43.9% in air servicemen and 53.9% in ground servicemen. The common symptoms were abdominal bloating (13.0%), belching (10.5%) and early satiation (9.7%) in air servicemen and early satiation (14.8%), abdominal bloating (14.7%), nausea (14.7%) in ground servicemen. The top 3 diseases in air force servicemen were functional bloating (7.2%), functional dyspepsia (6.9%) and CVS (5.1%). The total incidence of CVS was 5.05% in air force servicemen, 3.42% in air servicemen and 5.45% in ground servicemen. The component ratios were different or incompletely different in marital status, education level, blood type, age, military service length, BMI, and ranks of air force servicemen. Conclusion The total incidence of CVS is 5.05% in air force servicemen, 5.45% in ground servicemen and 3.42% in air servicemen. Younger age, shorter military service length, lower rank and education level are the risk factors for CVS when the constitution of air force servicemen is similar.