To examine miR-148a expression in the serum of patients with endometriosis (EMS), and to further explore the target of miR-148a in HS832.Tc cells and the effect of miR-148a on the proliferation of Hs832.Tc cells. The serum of non-EMS patients and EMS patients were collected and real-time quantitative PCR (qRT-PCR) was used to detect miR-148a in serum. The EMS cell line Hs832.Tc was cultured and transfected with miR-148aminic, miR-148a inhibitor to construct over expressing and interfering cell lines. Cell viability and apoptosis were detected. The dual luciferase assay identified a target relationship between miR-148a and ADAMTS5 and whether miR-148a regulates proliferation of endometriosis cells via ADAMTS5 was further validated. Compared with normal subjects, miR-148a was significantly reduced in serum of EMS patients (p<0.05). The area under the receiver operating characteristic curve for miR-148a for diagnosis of EMS was 0.91, which was statistically significant (p<0.01). The proliferation of Hs832.Tc cells was significantly inhibited and the cell apoptosis was increased after miR-148a over expression. The proliferation of Hs832.Tc cells was promoted and apoptosis was reduced by miR-148a down regulation. The dual luciferase report demonstrates that ADAMTS5 is a target gene of miR-148a. The addition of ADAMTS5 can directly promote apoptosis of Hs832.Tc cells. The expression of miR-148a in serum of EMS patients was decreased, and miR-148a targets ADAMTS5 to promote apoptosis in EMS cells.