Abstract: Causes of endometriosis remains unclear up to date，although it is a common benign disease in gynecologic clinic. Recent studies have shown that cyclooxygenase-2（COX-2） plays an important role in endometriosis，which exhibits an increasing expression in eutopic and ectopic endometrium. COX-2 can suppress apoptosis pathway of endometrial cells to promote the growth of endometriotic lesion by regulating the expression of anti-apoptotic proteins and pro-apoptotic enzymes；COX-2 can also facilitate angiogenesis to support the growth and proliferation of endometriotic cells，which is based on the increased expression of angiogenic factors. This article made an review of the role of COX-2 in pathogenesis of endometriosis.

Key words: Endometriosis, Prostaglandin-endoperoxide synthases, Angiogenesis inducing agents, Estrogens