Abstract: Objective To investigate the effect of estrogen receptor beta（ERβ） on osteocalcin production in human periodontal ligament fibroblast（HPLF） cells. Methods A short interfering RNA（siRNA） technique was used to inhibit ERβ expression in HPLF cells cultured with 17β-estradiol at a saturating concentration of 10-7mol/L.The amount of osteocalcin was determined with an osteocalcin ELISA kit. Results RT-PCR and Western blot showed that ERβ mRNA vector could specifically inhibit the expression of ERβ in HPLF cells.The osteocalcin level in HPLF cells was significantly higher in estradiol treatment group than in control group（P＜0.01）.However,no significant difference was observed in ERβ siRNA vector-transfected osteocalcin in HPLF cells between the two groups（P＞0.05）. Conclusion Estrogen may stimulate osteocalcin production in HPLF cells mainly via ERβ.