The invention discloses a capsule for increasing the bone density and a preparation method of the capsule. The capsule for increasing the bone density is prepared from glucosamine hydrochloride, chondroitin sulfate, calcium carbonate, vitamin K2, vitamin D3 and magnesium stearate. The capsule has the beneficial effects that the content of calcium absorbed by a human body is supplemented by virtueof calcium compounds easily absorbed by the human body in glucosamine hydrochloride, chondroitin sulfate and calcium carbonate, the adsorption of the human body to calcium and phosphorus can be increased by virtue of vitamin D3, the levels of plasma calcium and plasma phosphorus can reach saturation degrees, and the bone protein is generated by virtue of vitamin K2 and can generate sclerotin together with calcium, so that the osteoporosis is improved, the bone density is increased, and the fracture is prevented.