The invention discloses a biodegradable and medical tricalcium phosphate/gamma-polyglutamic acid composite and a preparation method thereof. According to the invention, an in situ complexing method is adopted for preparing the biodegradable and medical tricalcium phosphate/gamma-polyglutamic acid composite, the composite is formed by complexing tricalcium phosphate and gamma-polyglutamic acid by virtue of intermolecular group carboxylate radicals, tricalcium phosphate powder is deposited on a gamma-polyglutamic acid substrate, mechanical strength of the composite is enhanced under the action of a crosslinking agent, toughness of tricalcium phosphate is improved, and bone bonding ability and degradability of the tricalcium phosphate are improved, so that repair of bone defect can be promoted. Pore size of the composite is 60-280Mum, porosity range is 64-85%, weight loss ratio is 8.60-39.57% after the composite is soaked in 0.9% normal saline and stands still for three months at constant temperature of 37 DEG C, the composite has the characteristics that the tricalcium phosphate is uniformly distributed, the tricalcium phosphate and the gamma-polyglutamic acid are tightly combined and degradation rate is continuous and adjustable, the pore size of the composite is appropriate, and the composite can be taken as bone repair material to be applied to the biomedical fields such as bone tissue engineering.