A bone implant composite comprising a collagen matrix and a calcium-based mineral, the calcium-based mineral having a particle size of 25-2000 .mu.m 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 .mu.m, a density range of 0.02-0.8 g/cm.sup.3, a tensile strength range of 0.4-100 kg/cm.sup.2, and a compression modulus range of 0.2-10 kg/cm.sup.2. Also disclosed are methods of preparing the above-described composite.