Abstract: Abstract: Objective To study the expression of pericyte and make further discussion about the association between pericyte and angiogenesis in the endometriosis. Methods the main group consisted of 20 ectopic endometrium 、20 eutopic endometrium during proliferation phase,20 eutopic endometrium during secretory phase of patient with endometriosis .The control group presented 20 normal endometrium during proliferation phase and 20 normal endometrium during proliferation phase of women without entometriosis.The histological morphology ,mean density of microvessel(MVD),pericytes number（PN） as well as the average ratio of pericyte to endothelial cells in microvessels were measured by immunohistochemical and morphological assesses .Results The expression of MVD was increased from the ectopic endometrum tissue ,eutopic endometrum to normal endometrum,while the expression of PN and PN/MVD was opposite.we also found that the PN in eutopic endometrum was slightly lower than it in normal endometrium ,no mater in secretory stage or proliferativa stage,there was no statistical difference between them.But The difference of the PN/MVD had significant meaning (P<0.01). Conclusion Pericytes play an important role in the angiogenesis of the endometriosis ,pericyte coverage contributing to a mature functional vasculature of endometriosis.

Key words: endometriosis, angiogenesis, microvessel, pericyte