Objective To explore the association between dietary behavior and weight change in medical staff during the COVID-19 pandemic， and provide the scientific basis for their nutrition and health improvement.Methods From May to July 2022， 1 487 doctors and nurses from 12 COVID-19 designated hospitals in Northeast China were randomly recruited to participate in the survey. After excluding invalid questionnaires， 1 352 valid questionnaires were obtained. Data were collected by self-compiled general questionnaire， eating behavior indexes and emotional eating scale， and analyzed by statistical methods such as analysis of variance （ANOVA） and linear regression model.Results Among the medical staff of COVID-19 designated hospitals， there were 485 （35.9%） individuals with stable weight （±3%）； individuals with substantial weight loss （<5%）， moderate weight loss （3%-5%）， moderate weight gain （3%-5%）， substantial weight gain （>5%） were 8.2%（111/1 352）， 22.7%（307/1 352）， 23.6%（319/1 352） and 9.6%（130/1 352）， respectively. The results of ANOVA showed that there were significant differences of irregular diet， unbalanced nutrition， high oil diet， high salt diet， high carbohydrate diet， beverage intake， and emotional eating behaviors between different weight change groups （P<0.05）. However， the drinking behavior between the five groups did not get statistical significance （P>0.05）. The results of multivariate linear regression indicated that irregular diet， high carbohydrate diet， beverage intake， emotional eating and income were risk factors of weight change （P<0.05）； marriage and exercise behavior were protective factors of weight change （P<0.05）.Conclusion The weight management situation of Chinese medical staff was unfavourable during the COVID-19 pandemic. Unhealthy eating behavior was the main risk factor for weight change in medical staff， and a healthy lifestyle could effectively control and maintain weight. Medical staff should improve their dietary patterns and weight management， which benefits their medical service quality and patient safety.