Abstract： Objective To investigate the prevalence and risk factors of fatty liver in army aviators and provide evidence for aeromedical service. Methods The height，weight，diagnosis of 443 army aviators were got from their case history by random sampling.The related factors were investigated through questionnaire.The prevalence and risk factors of fatty liver were determined by multivariate Logistic regression，t test，chi-square test，Fisher exact probabilities test，and Cochran armitage trend test. Results①The fatty liver prevalence of army aviators was 10.61％.The fatty liver prevalence of army aviators was higher than civil aviators and had no difference with army pilots.②The risk factors of fatty Iiver were enumerated in order of corrected coefficient of regression as follows：body mass index(BMI)，age，daily alcohol drinking，flight time and area.③The mean age，BMI，daily alcohol drinking and flight time of fatty liver group were significantly higher than those without fatty liver.The prevalence of fatty liver increased with age，BMI，daily alcohol drinking and flight time,and was different in each area.The fatty liver prevalence in each area was enumerated as follows：central plains，southwest，eastern China and northern China.Conclusion ①There was a higher prevalence of fatty liver among army aviators.②There was a lower prevalence of fatty liver among young army aviators.But it increased quickly with aging and flight time.③Overweight,and flight were the important risk factors of fatty liver in army aviators.④Geography，environment and eating habit were related with fatty liver in army aviators.