Objective The study was designed to investigate the cause and the epidemiological characteristics of a hepatitis A outbreak in a rural middle school, and discuss the outbreak factors and control measures. Methods Descriptive epidemiological analysis was performed on this outbreak. Results A total of 69 hepatiutis A cases were reported during the outbreak in Fengshan town, Bobai county, Guangxi with an attack rate of 3.62%. The attack rates in Fengshan No.2 middle school and in Fengshan primary school were 4.58% and 0.45% respectively with significant statistical difference between them. In Fenghsan No.2 middle school, 63 cases occurred among the resident students with the attack rate of 6.09% (63/1035), while 3 cases occurred among the nonresident students with the attack rate of 0.10% (3/301), and the two rates had statistical difference (Х2 = 12.87 , P 0.05). Most hepatitis A cases occurred within 11-20 days after the occurrence of the first case, accounting for 75.36% of total cases, and most cases were at the age of 14-16 years, accounting for 79.71% of total cases. Conclusion Poor sanitation and water pollution in school, low coverage rate of hepatitis A vaccine, immunization gaps, delayed report of the outbreak, failure to take effective control measures and poor hygiene habits among the students were the causes of this outbreak. By comprehensive prevention and control measures such as announcing the infection source, strict management of infection source, disinfection in epidemic area and protecting susceptible population, the outbreak was controlled effectively.