【Abstract】 Objective To investigated expression of TGFβ1 in the airway remodeling of asthma rat model and explore the possible mechanism of Salvia miltiorrhiza injection.Methods 24 healthy SpragueDawley rats were randomly divided control group, Asthmatic group and Salvia miltiorrhiza injection treatment group. The Asthmatic group were sensitized with an intraperitoneal injection of 1ml (100mg) OVA complexed with 100mg Imject Alum (AL(OH)3). The rats were challenged with an aerosol generated from an OVA solution (1% OVA w/v in saline) for 30 minutes in fourteen consecutive days. Salvia miltiorrhiza injection treatment group were sensitized and challenged the same as the asthmatic group, pretreated with Salvia miltiorrhiza injection 15ml/kg body weight/d and given intraperitoneally every day before OVA challenged. The same dose of saline was administered in control group. The WBC counts in BALF and lung specimen analysis were used to describe lung tissue inflammation. The concentrations of TGFβ1 in BALF were measured by LISA. Lung tissues were sliced and stained with HE. The following morphological parameters such as airway wall basement membrane permeter (Pbm), total bronchial wall area (WAt), the inner wall area (WAi) and the area of smooth muscle (WAm), which reflect the remodeling of airway, were measured by computerized image analysis system. The relationship among the degree of EOS and the expression levels of TGFβ1 in BALF, the concentrations of TGFβ1 and thickness of airway wall were also investigated. Results Salvia miltiorrhiza injection pretreatment significantly reduced the total cell, eosinophils, the expression levels of TGFβ1 in the BALF, and attenusted airway wall thickening, smooth muscle hyperplasia when compared with asthmatic group; There was a significant positive correlation between the expression of TGFβ1 and EOS counts in BALF(r=085,P＜001). The expression of TGFβ1 shows a significant positive correlation with the area of smooth muscle(r=081,P＜001).Conclusion Early pretreatment with Salvia miltiorrhiza injection partly inhibited the development of airway inflammation and airway remodeling by downregulating the expression of TGFβ1 , which may through downregulating the expression of EOS.