Objective To investigate the effects of transforming growth factor beta (TGF-β) on airway remodeling in obese asthmatic mice and intervention effects of pirfenidone. Methods Seventy-five C57BL/6J mice were randomly divided into five groups, namely a blank control group (group A), an obese group (group B), an obese asthmatic group (group C), a budesonide treatment group (group D) and a pirfenidone treatment group (group E). The mice in the B, C, D, and E groups were fed with high fat diets, then the mice in the C, D, and E groups were sensitized and challenged with ovalbumin (OVA) to establish the model of chronic obese asthma. The mice in group A were fed with normal diets, sensitized and challenged with normal saline. The mice in group D were treated with budesonide (0.5 mg/ml), and the mice in group E were treated with pirfenidone (300 mg/kg). After 4 weeks of treatment, the total number of white cells as well as the percentage of leukocytes, eosinophils, neutrophils and macrophage in bronchoalveolar lavage fluid (BALF) were counted. ELISA and Western blot were used to evaluate the expression of TGF-β. The pathological changes of mice were observed under light microscope by HE and periodic acid-Schiff staining. Meanwhile the remodeling indices were measured including total bronchial wall area (WAt), smooth muscle area (WAm), and bronchial basement membrane perimeter (Pbm). Results The levels of leukocyte and eosinophils in BALF, expression of TGF-β, WAt/Pbm and WAm/Pbm in group C were higher than those in group A, B, D, and E (allP<0.05). The levels of eosinophils in BALF, WAt/Pbm in group E were lower than those in group D (allP<0.05). The level of TGF-β decreased in a sequence of group C>D>E>B>A (allP<0.05). The expression of TGF-β was in a positive correlation with eosinophil percentage in BALF (r=0.79,P<0.01). Conclusions The expression of TGF-β in the airway of obese asthmatic mice is closely related to airway inflammation, airway hyper-secretion and airway remodeling. Pirfenidone can effectively inhibit the expression of TGF-β and improve airway remodeling.