Abstract: Objective： To investigate the biological chatacteristics of periodontal ligament stem cells (PDLSCs) in inflammation microenvironment. Methods： PDLSCs were isolated from the periodontal ligament tissues of periodontitis patients (P-PDLSCs) and healthy controls (H-PDLSCs) by limiting dilution technique. Cell phenotype was analyzed by flow cytometry. Cell cycle analysis, MTT viability assay and clone-forming ability were used to study the proliferative ability. Osteogenic and adipogenic induction were performed to study the multipotential differentiation. Results：PDLSCs were successfully isolated from periodontitis patients and healthy controls. Both H-PDLSCs and P-PDLSCs expressed stem cell markers of mesenchymal stem cells and the overall expression patterns were similar between two groups. The proliferative ability of P-PDLSCs was strikingly higher than that of H-PDLSCs. The osteogenic and adipogenic ability of P-PDLSCs was lower than that of H-PDLSCs. Conclusions：In inflammatory microenvironment, PDLSCs exhibited increased proliferative ability but impaired differentiation capacity.