An RGD polypeptide grafted poly (glycolic acid-L-lysine-L-lactic acid) / β-tricalcium phosphate composite material is composed of β-tricalcium phosphate particles and RGD polypeptide grafted poly (glycolic acid-L-lysine-L-lactic acid) with mass ratio of 1:10∼1:100, in which the β-tricalcium phosphate particles are uniformly dispersed in the RGD polypeptide grafted poly (glycolic acid-L-lysine-L-lactic acid) matrix. The preparation method includes that poly (glycolic acid-L-lysine-L-lactic acid) is polymerized with GRGDY short peptide (glycin-arginine-glycin-aspartic acid-tyrosine sequence) to obtain RGD polypeptide grafted poly (glycolic acid-L-lysine-L-lactic acid), and then RGD polypeptide grafted poly (glycolic acid-L-lysine-L-lactic acid) is compounded with β-tricalcium phosphate particles. The composite material exhibits favorable biocompatibility, cellular affinity, biodegradability and mechanical behavior, and can avoid aseptic necrosis of tissues, which may be used as nerve guide or porous bone scaffold for repairing nerve tissue and bone tissue.