Objective To investigate the impact of dietary protein intake on the prevalence of type 2 diabetes in adult residents, and to provide a reference for formulating diabetes prevention and control measures. Methods The research was based on cross-sectional survey data from the Nutrition and Health Follow-up Study of Chinese Residents in Chongqing (2021). Energy and nutrient intake was calculated in combination with the Chinese food composition table. Multivariate logistic regression was used to analyze the association between dietary protein and diabetes, and then restricted cubic spline regression (RCS) was used to analyze the dose-response relationship between dietary protein intake and the development of diabetes. Results Among the 1 415 adult residents, dietary intake of total protein, animal protein, and plant protein was 69.69g/d, 26.26g/d, and 43.43g/d, respectively. The ratio of protein to energy supply was 14.31%, and the prevalence of diabetes was 18.02%. Comparing with the residents in the first percentile of total dietary protein intake, the multivariable-adjusted odds ratios of those in the second and third percentile were 1.754 and 2.453 respectively. Comparing the residents in the third percentile with those in the first percentile, the multivariable-adjusted odds ratios of diabetes were 1.592 for protein energy supply ratio, and 1.558 for animal protein intake. Conclusion High protein intake, high protein energy supply ratio and high animal protein intake may increase the risk of diabetes, and different types of protein may have different effects on diabetes.