Objective To identify the latent classes of exercise self-efficacy in patients with type 2 diabetes mellitus (T2DM), to analyze its relation with physical activity behavior stage, and to provide reference for developing targeted intervention. Methods A total of 315 T2DM patients were investigated using a demographic data questionnaire, the Exercise Self-efficacy Scale, the International Physical Activity Questionnaire, and a stage algorithm measuring the Four steps from Inactivity to activity Theory (FIM Model) . Latent profile analysis was performed to identify patterns of exercise self-efficacy and ordinal logistic regression was used to determine the predictors of physical activity behavior stage. Results The participants reported 45.52±19.78 on exercise self-efficacy. The best model consisted of 4-classes:high exercise self-efficacy (class 1:18.1%), moderate to high exercise self-efficacy (class 2:30.1%), low to moderate exercise self-efficacy (class 3:34.0%), and low exercise self-efficacy (class 4:17.8%). Duration of diabetes and patterns of exercise self-efficacy were the influencing factors of stage of physical activity behavior change (both P<0.05). Conclusion Exercise self-efficacy is an important predictor of physical activity behavior stage, high lighting the need to tailor interventions based on patient′s distinct type of exercise self-efficacy.