Abstract: Objective: To investigate the expressions of transforming growth factor-1(TGF-1) and connective tissue growth factor (CTGF) in viral myocarditis.Methods: Thirty-six male Balb /c mice were divided into two groups randomly: control group and model group.Model group was established by Cox-sackie virus B3 induced viral myocarditis.Six mice in each group were killed on days 7， 14 and 28 respectively.The hearts were weighed and fixed with 4% paraform，histological cross sections were stained with hematoxylineosin and myocardial histopathoplogic scores were counted under optical microscope.The protein expressions of myocardial collagen Ⅰ and Ⅲ were examined by immunohistochemical method and analyzed using a computer assisted procedure， then the area of collagens were calculated.The protein expressions of TGF-1 and CTGF were also examined by immunohistochemical method， and the absorbance and area of positive cells were measured after standard gray correction， the antigen contents were calculated by product of absorbance and area.Results: In contrast to control group， the histopathoplogic scores， expressions of myocardial collagen Ⅰ and Ⅲ，TGF-1 and CTGF were increased markedly in Cox-sackie virus B3 infected group (P0.01) .The expression of myocardial collagen Ⅲ was correlated with TGF-1 and CTGF positively (P0.05) ， the expression of TGF-1 was correlated with CTGF positively (P0.05) .Conclusions: TGF-1 and CTGF participate in the occurreuce and development of myocardial fibrosis of viral myocarditis.