Objective To evaluate the dietary quality of De'ang nationality residents over 18 years old in Yunnan Provinceusing the new adjusted Diet Balance Index (DBI_16), and to provide scientific basis for improving the nutritional status of De'ang residents and formulating health promotion strategies. Methods A food-frequency questionnaire was used to investigate the diet of De'ang residents, and the new adjusted dietary balance index (DBI_16) was used to evaluate the dietary quality. Results The dietary quality of De'ang nationality residents over 18 years old in Yunnan Province was in a moderately imbalanced state (DQD=42), and the main problem was insufficient dietary intake (LBS = 26). The dietary imbalance among men, 65-79 years old and low-income people was serious. The intake of milk, vegetables, fruits and aquatic products was the most insufficient and people who met the recommended intake levels of these foods were 2%, 34.7%, 31.8%, and 36%, respectively. Meanwhile, there existed the problem of excessive intakes among people studied in the present investigation. Pople who consumed more than recommended amount of Cereal food, livestock and poultry meat, and edible oil accounted for 76.9%, 60.4% and 63.5%, respectively. Conclusion The dietary structure of De'ang residents over 18 years old in Yunnan Province is unreasonable. The problems of both insufficient and excessive dietary intakes exist. Education on balance diet should be conducted to improve nutrition and health status of De'ang nationality residents.