The invention provides a preparation method of high-calcium milk, a preparation method of high-calcium low-fat milk, a high-calcium milk product and a high-calcium low-fat milk product. The preparation method of the high-calcium milk and the preparation method of the high-calcium low-fat milk comprise the following steps of firstly preparing high-calcium protein powder, sweetening substances and milk, wherein high-calcium protein powder which is obtained by separating and concentrating micellar casein, and of which the calcium content is greater than or equal to 2000mg / 100g is used as the high-calcium protein powder, based on the total amount of the high-calcium milk being 100%, the percentage by weight of the sweetening substances is 0.5-0.8%, the total content of the high-calcium proteinpowder and the milk is within the limit that the content of calcium in the high-calcium protein powder and the milk in finished products of the high-calcium milk is greater than or equal to 120mg / 100ml, and full fat raw milk of which the calcium content is 95-115mg / 100g is used as the milk; during preparation, firstly, uniformly mixing the high-calcium protein powder with the sweetening substances to obtain a mixture, then pouring the mixture into milk which is preheated to 20-30 DEG C in advance, and performing uniform mixing; then performing rapid cooling to 4-10 DEG C; and finally, performing preheating to 65-70 DEG C, performing homogenizing, performing sterilizing, performing cooling and performing filling to obtain finished products. The high-calcium milk product can meet health requirements of consumers for pure milk products free from food additives.