The action mechanism of matrix metalloproteinases-2 (MMP-2) and tissue inhibitor of metalloproteinases-2 (TIMP-2) in the genesis, development and degeneration of haemangioma was in-vestigated by detecting their expression in the tissue of haemangioma in different phases by using the immunohistochemistry. Fifty paraffin-embedded specimens of skin capillary haemangioma were col-lected, which were documented in the Department of Pathology, Renmin Hospital of Wuhan University from 2000 to 2006. All samples were stained by regular HE method, and proliferative cell nuclear anti-gen (PCNA) was tested by immunohistochemical S-P method, The samples were classified according to the Mulliken criteria and the expression patt of PCNA. Immunohistochemical S-P method was ap-plied to detect the expression of MMP-2 and TIMP-2 in proliferative and degenerative phases of cuta-neous capillary haemangioma, and in normal skin tissues. In combination with the detection of the ex-pression of factor Ⅷ-related antigen, it was verified that in haemangioma tissues, the cells expressing MMP-2 and TIMP-2 were vascular endothelial cells. The MMP-2 and TIMP-2 expression was quantita-tively analyzed by image analysis system (HPIAS-1000), and one-way ANOVA(107) and SNK(q) test were done to analyze average absorbance (A) and positive area rate of immunohistochemically positive particles by using SPSS11.5. The results showed: (1) Among 50 samples of haemangioma, there were 26 proliferative haemangiomas, and 24 degenerative haemangiomas, respectively; (2) The expression of MMP-2 was weak in normal vascular endothelial cells, cytoplasm of connective tissues and extracellu-lar matrix around blood vessels. The expression of MMP-2 in proliferative group was significantly higher than in degenerative group and control group (normal skin) (P<0.05), but there was no statisti-cally significant difference between the latter two groups; (3) TIMP-2 was highly expressed in normal tissues, degenerative vascular endothelial cells, cytoplasm of connective tissues and extracellular matrix around blood vessels. The expression level of TIMP-2 in proliferative phase was significantly lower than in degenerative phase (P<0.05), and the expression of TIMP-2 in proliferative phase was signifi-cantly different from that in degenerative phase and normal tissues (P<0.05). It was concluded that in proliferative phase of haemangioma, MMP-2 may promote over-proliferation of endothelial cells of haemangioma, and in degenerative phase, TIMP-2 can inhibit the proliferation of endothelial cells of haemangioma. The two substances play important roles in the genesis, development and degeneration of haemangiomas.