ObjectiveTo study the expressions of Ki-67 and p53 in the surface cells and polygonal cells in pulmonary sclerosing hemangioma(PSH)and investigate the relation of cell proliferation index and biological behaviour of the tumor.MethodsDouble-staining immunohistochemistry was used to detect the expressions of Ki-67 and CK8/18 protein. Double immunofluorescence staining was used to detect the expressions of p53 and AE1/AE3 protein. ResultsThe positive signal of AE1/AE3 and CK8/18 were localized in cytomembrane of surface cells. The positive signal of Ki-67 and p53 were localized in cell nucleus of the two kinds of cells.The positive rate of Ki-67 was under 1％ in surface cells and 1％-10 ％ in polygonal cells. p53 protein was mainly expressed in polygonal cells (6/9, 33.3 ％) and only exsited in seldom surface cells.ConclusionThere are differences on cellular morphous and immunophenotype between the surface cells and polygonal cells.The proliferation index and gene mutation are all predominant in polygonal cells than in surface cells. The biological behaviour of PSH maybe mainly be decided by the polygonal cells.