The invention discloses bone-strengthening liquid calcium and a preparation method thereof. The liquid calcium comprises the following raw materials in parts by weight: 1-100 parts of deer bone, 1-100 parts of red date, 1-100 parts of dog bone, 1-100 parts of pig bone, 1-100 parts of seabuckthorn fruit, 1-100 parts of deep sea fish skin, 1-100 parts of medlar, 1-100 parts of black sesame, 1-100 parts of pearl, 1-100 parts of dragon bone, 1-100 parts of radix pseudostellariae, 1-100 parts of donkey-hide gelatin, 0.6-60 parts of milk powder, 0.6-60 parts of lactose, 0.6-60 parts of sucrose, 2-20 parts of calcium lactate, 2-20 parts of calcium gluconate and 0.1-10 parts of vitamin D. The bone-strengthening liquid calcium is scientific in compatibility, can enhance the body immunity, tonify Qi, promote body fluid secretion, tonify lung, strengthen spleen, nourish and tonify kidney, generate sperm, nourish blood, resist fatigue, increase the bone density, strengthen tendons and bones, supplement calcium, promote calcium absorption and the like after long-time use, and has multiple efficacies.