Objective: To explore the effect of dapagliflozin on serum CTGF and TGF-β1 in patients with type 2 diabetes mellitus complicated with paroxysmal atrial fibrillation The influence of Factor-β,TGF-β1) expression.Methods: A total of 100 patients with type 2 diabetes mellitus complicated with paroxysmal atrial fibrillation admitted from June 2022 to June 2025 were included in the study,The grouping method for the enrolled patients was the ball-touching method. Fifty patients who received conventional treatments (hypoglycemic, anticoagulant, antiplatelet, etc.) were included in the control group,Fifty patients treated with dapagliflozin in combination (10mg each time, qd) were included in the study group,After 3 months of continuous treatment, the changes in cardiac function, atrial fibrillation indicators, fibrosis indicators, and levels of oxidative inflammatory stress factors in the two groups were evaluated.Results: Compared with the levels of atrial fibrillation indicators, the group with better improvement in cardiac function after treatment was the study group (P<0.05).The comparison of TGF-β1 and CTGF levels between the two groups of patients showed that the group with more significant reduction after treatment was the study group (P<0.05).After treatment, the levels of various oxidative inflammatory stress factors in both groups improved significantly compared with those before treatment, and the improvement in the study group was even better (P < 0.05).Conclusion: On the basis of conventional treatment for patients with type 2 diabetes mellitus complicated with paroxysmal atrial fibrillation, combined administration of dapagliflozin can inhibit myocardial fibrosis and paroxysmal atrial fibrillation by suppressing the expression of serum TGF-β1 and CTGF, improve cardiac function, and also help to inhibit oxidative inflammatory stress, which is of great value in controlling disease progression and improving prognosis.