Abstract: Objective To develop a novel porous poly lactic-acid(PLA)/bone matrix gelatin(BMG)bioactive composite biomaterial with supercritical carbon dioxide(SC-CO2)extraction and determine the optimal proportion of the ingredients by evaluating the physical and chemical characteristics and cellular compatibility of the composites.Methods The PLA/BMG composite biomaterials with various PLA/BMG proportions were prepared with SC-CO2 technique and evaluated by macroscopic observation,porosity and mechanical assessment,and scanning electron micrograph(SEM).The optimal proportion of PLA/BMG was determined in conjunction with the results of cellular compatibility evaluation.Results BMG proportion in BLA/BMG composite biomaterials prepared with SC-CO2 technique was positively associated with the cellular compatibility and porosity,and inversely with the mechanics of the prepared composite.The results showed BMG content of 30% in PLA/BMG composite was optimal.Conclusion The composite with PLA and BMG proportion of 7:3 possesses good physical and chemical characteristics and cellular compatibility,suggesting its potential as the bone implant biomaterial and bone-tissue engineering scaffold.