FIELD : medicine.SUBSTANCE : invention refers to medicine and discloses a biomaterial for the manufacture of heart valve prostheses and a method for preparing it. Biomaterial includes bovine pericardium coated with nanodiamonds of detonation synthesis, having positive electrokinetic potential in water, with content of nanodiamonds of 1.5 to 4?mg per gram of biological tissue, with average size of aggregates from 17 to 28?nm on surface of biomaterial.EFFECT : biomaterial is characterized by high strength and wear resistance and is intended for improving mechanical properties of materials for making artificial heart valves.7 cl, 4 dwg, 2 ex