Osteoporosis, a calcium deficiency, is a common disease in the elderly. Calcium is not only the main mineral component that makes up bone tissue, but also plays an important role in various physiological and biochemical processes in the body. Calcium supplementation is particularly important. However, most people believe that the more calcium the better, and often use calcium supplements in excessive doses in their lives. In fact, if calcium is taken in excess or incorrectly, not only will it not be a good supplement, but it will also affect its absorption in the body. The human gastrointestinal tract absorbs about 200mg of calcium ions each time, if excessive, affecting its saturation, the excess calcium will be excreted and affect the absorption. The use of calcium in excessive doses cannot serve the purpose of treating osteoporosis. We suggest that the scientific approach is to take the right amount many times. It is recommended to take 200mg each time, 2-3 times a day, preferably 1-1.5 hours after meals, so as to avoid the effect of food on calcium and maximize its utilization. In addition, foods with high calcium content should be consumed, such as: soy milk, milk, fish and shrimp. Sun exposure is also essential to promote calcium absorption.