Objectives:To study the pathological behavior and the value of transforming growth factor β1(TGF-β1) in predicting prognosis in pulmonary hypertension associated with congenital heart disease.　Methods:Lung tissues from 29 patients with congenital heart diseases associated with pulmonary hypertension were examined by surgical biopsy of the lung. All samples were examined for the expression and localization of TGF-β1 by immunohistochemical technique with anti-TGF-β1 antibody.　Results:Twenty-six out of 29 showed positive staining of intracellular endotheliocyte TGF-β1(89.65%),16 samples showed extracellular matrix TGF-β1 staining(55.17%).Statistically, there was significant difference between Ⅰ～Ⅱ and Ⅲ～Ⅵ pathological degrees in extracellular matrix(P<0.05).　Conclusions: TGF-β1 plays an important biological role in the formation of pulmonary hypertension after congenital heart disease. It is conductive in predicting prognosis.