Objective To explore the effect of macromolecule crowding on the proliferation and osteogenic differentiation of adipose-derived stem cells(ADSCs).Methods The macromolecular crowders Ficoll 400 and Ficoll 70 were mixed with the concentrations of 25 mg/mL and 37.5 mg/mL to produce 50 mg/mL Fc mixture for the in vitro culture of ADSCs.CCK-8 test,dsDNA kit and BCA kit were used to quantitatively determine the effect of macromolecule crowding on the proliferation capacity of ADSCs under standard conditions.And the cells were subjected to osteogenic induction at different time points.Alizarin red staining was used to detect the changes in the osteogenic differentiation ability of ADSCs.Results CCK-8 test showed that the macromolecule crowding promoted the proliferation of stem cells.dsDNA analysis and BCA quantitative detection showed that the macromolecule crowding promoted the synthesis of ADSCs DNA and proteins.In addition,calcium nodules of the osteoblasts were enhanced showed by alizarin red staining,which proved that the osteoblastic differentiation ability was improved.Conclusion The macromolecular crowding niche promotes the osteogenic differentiation and proliferation of ADSCs in vitro.