Objective To investigate the effects of oestrogen-receptor(ER), progesterone-receptor(PR), vascular endothelial growth factor(VEGF) and kinase insert domaincontaining receptor(KDR) in uterine bleeding induced by intrauterine device(IUD). Methods Immunohistochemical method was used to detect the expressions of ER, PR, VEGF and KDR in endometrium from IUD bleeding group and normal control group, respectively. Microvessel density(MVD) was evaluated by using anti factor Ⅷ-related antigen (F8-RA) antibody to mark stromal microvessels. Results The expressions of ER, VEGF and KDR were significantly higher in IUD-induced endometrium bleeding group than those in control group(P0.05). MVD was significantly higher in IUD-induced endometrium bleeding than that in normal endometrium(P