To detect the high-frequency loss of heterozygosity (LOH) chromosome regions for ectopic endometrium of ovarian endometriosis (EMs) and to investigate the significance of high-frequency LOH chromosome regions in EMs, we obtained ectopic endometrium by laser capture microdissection (LCM (22 samples)), manual capture microdissection (MCM (18 samples)), and routine dissection (14 samples), respectively. After restriction and circularization-aided rolling circle amplification (RCA-RCA), LOH was detected at 12 microsatellite (MS) loci. The frequency of LOH was 59.09% (13/22) in LCM group, 61.11% (11/18) in the MCM group and 21.43% (3/14) in the routine dissection group. The latter was significantly lower when compared with the former two (p < 0.05). In the LCM group, candidate chromosome regions 17q21.31 and 9p21.3 had LOH frequencies of 23.8 and 13.6%, respectively. The highest LOH frequency was detected at the locus AAAT2 on chromosome 17q21.31 (40%). The chromosome region with the highest frequency of LOH for ectopic endometrium was 17q21.31, especially at the AAAT2 locus, which prompted that down regulation of the candidate genes nearby the locus might be one of the mechanisms of EMs pathogenesis. LCM combined with RCA-RCA is a reliable technique for analyzing endometrial LOH at multiple MS loci. MCM combined with RCA-RCA, which provided similar results, was more cost-effective.