Objective　To investigate the expression of CD1a and CD83 which were themarkers of immature dendritic cells (imDCs) and mature dendritic cells (mDCs) respectively in endometrial tissue of endometriosis, and explore the role of DCs at different stages in the occurrence and development of endometriosis.　Methods　30 cases with chocolate cyst in the proliferative phase confirmed by pathological examination were selected, the ectopic endometrium tissues and the ectopic endometrium tissues were taken as eutopic endometrium of EMS group, ectopic endometrium of EMS group EMS and in the endometrium, another 30 cases of normal endometrial tissue were taken as control group. Immunohistochemical straining were used to detect the location and the expressions of CD1a and CD83, and western blotting were used to detect the expressions of CD1a and CD83 　Results　The CD1a and CD83 positive cells are scattered among stromal cells; The expression of CD1a increased in control group, ectopic endometrium group and eutopic endometrium group, and the difference between groups was significant (P<0.01); the expression of CD83 decreased in control group, ectopic endometrium group and eutopic endometrium group, and the difference between groups was significant (P<0.01). Conclusion Compared with non EMS patients, the increase of imDCs and the decrease of mDCs in local endometrium in endometriosis may play important roles in the occurrence and development of EMS.