Calcium supplementation is indispensable for scientific height increase, and parents know this. The role of vitamin D in promoting calcium absorption and scientific increase in height should not be ignored. Vitamin D, scientifically known as calcitriol, is a small molecule that promotes both intestinal absorption of calcium and renal reabsorption of calcium. It is also known as the “sunshine vitamin” and can be produced by the body simply by exposure to the sun. In addition, the amount of calcium intake, the ratio of dietary calcium (calcium food) and phosphorus content, the dissociation state of calcium into the intestine, the amount and type of protein (protein food) in the food, the physiological state of the gastrointestinal tract, etc., can affect the absorption of calcium.