Objective To analyze the prevalence and risk factors of fatty liver among young and middle-aged workers on a tropical island. Methods Questionnaire survey and physical examination were conducted among young and middle-aged workers on a tropical island. Data on general health status, dietary and lifestyle habits, and other common diseases were collected. Participants were classified into fatty liver and non-fatty liver groups based on hepatic ultrasonography findings. Between-group differences were analyzed, and multivariate logistic regression analysis was performed to identify influencing factors of fatty liver. Results A total of 295 individuals aged 30-45 years were enrolled. Ultrasonography revealed that 82 individuals had fatty liver, yielding a prevalence of 27.80%. Compared with the non-fatty liver group, the fatty liver group was older and had higher proportions of overweight/obesity, salty/oily/sweet/spicy diet, less/occasional exercise, and comorbidities including dyslipidemia, abnormal liver function, and hyperuricemia (all P＜0.05). Multivariate logistic regression analysis showed that overweight/obesity (odds ratio [OR] ＝6.399, 95% confidence interval [95%CI] 3.429-12.797, P＜0.001), salty/oily/sweet/spicy diet (OR＝2.161, 95%CI 1.246-3.826, P＝0.023), less/occasional exercise (OR＝2.001, 95%CI 1.203-3.348, P＝0.025), and hyperuricemia (OR＝3.430, 95%CI 1.866-6.395, P＜0.001) were the independent risk factors for fatty liver. Conclusion The prevalence of fatty liver is high among workers aged 30-45 years on this tropical island. Overweight/obesity, salty/oily/sweet/spicy diet, less/occasional exercise, and hyperuricemia may be risk factors of fatty liver. Regular monitoring and early intervention are recommended for individuals with these risk factors.