Abstract： Objective To evaluate the effect of platelet-rich fibrin extract (PRFe) on proliferation and differentiation and F-actin cytoskeleton of osteoblasts.Methods The experimental group used the α-minimum essential medium(α-MEM) containing PRFe(10％ fetal bovine serum),and the control group used the α-MEM (10％ fetal bovine serum).The number of the osteoblasts at 1st,3rd,5th d was detected by methyl thiazolyl tetrazolium(MTT) assay,and the differentiation of osteoblast at lst,3rd,5th,7 th d detected by the activity of alkaline phosphatase(ALP).The alizarin red dye was used to observe the number of calcium nodus at 14th,21st d.The F-actin cytoskeleton was evaluated by confocal laser scanning microscope (CLSM) at 3rd,6th,9th,12th h.The level of osteogenetic biomarkers osteocalcin(OCN) and core-binding factor α1 (Cbfα1) at 3rd,7th d were quantified by real-time PCR.Results A significant increase of absorbance at 1st,3rd,5th d was showed in experimental group (0.336 ± 0.011,0.571 ± 0.039,0.787 ± 0.050) compared to control group (0.300 ± 0.021,0.387 ±0.040,0.527 ±0.034) (P ＜0.05).The absorbance of experimental group at lst,3rd,5th,7th d(0.146 ± 0.014,0.199 ±0.017,0.390 ±0.020,0.492 ±0.019) was significantly higher than that of control group(0.115 ± 0.014,0.145 ± 0.015,0.190 ± 0.015,0.230 ± 0.026) (P ＜ 0.05).The integrated absorbance of the calcium nodus in experimental group at 14th,21st d (22.119 ± 3.694,31.528 ± 3.162) was significantly higher than in control group(8.498 ±2.041,15.162 ±2.526) (P ＜0.05).The Cbfα1 and OCN gene expression in experimental group was higher than in control group (P ＜ 0.05).Conclusions PRFe could enhance the proliferation and differentiation of osteoblasts and promote the spread of F-actin cytoskeleton.