Abstract: Objective： To compare the level of acetyltransferase KAT2A in periodontal ligament stem cells derived from healthy individuals (H-PDLSCs) with periodontal ligament stem cells derived from periodontitis individual (P-PDLSCs). And to determine the effect of acetyltransferase KAT2A on osteogenic differentiation potential of PDLSCs. Methods： Human PDLSCs were cultured and cloned with limited diluted method. Quantitative RT-PCR and Western Blot were used to examine different expression of acetyltransferase KAT2A in two kinds of PDLSCs. Quantitative RT-PCR, Western Blot and Alizarin Red Staining were used to determine osteogenic differentiation potential of PDLSCs with gene KAT2A knockdown. Results： Quantitative RT-PCR and Western Blot showed that lower expression of KAT2A was detected in P-PDLSCs compared with that of H-PDLSCs, with statistical significance(P<0.05). Quantitative RT-PCR, Western Blot and Alizarin Red Staining indicated that osteogenic differentiation potential was inhibited in H-PDLSCs with KAT2A knockdown and the effect was statistically significant(P<0.05). Conclusions： Periodontitis might repress expression of KAT2A in PDLSCs, which associates with osteogenic differentiation potential.