A bone implant composite comprising a collagen matrix and a calcium-based mineral, the calcium-based mineral having a particle size of 25-2000 mum and being interspersed in the collagen matrix; wherein the bone implant composite contains 3-60% by weight the collagen matrix and 40-97% by weight the calcium-based mineral, and has a pore size of 50-500 mum, a density range of 0.02-0.8 g/cm3, a tensile strength range of 0.4-100 kg/cm2, and a compression modulus range of 0.2-10 kg/cm2. Also disclosed are methods of preparing the above-described composite.