Soymilk and milk are both high in nutritional value. Milk is rich in protein and higher in calcium, while soymilk is richer in lecithin.
Every 100g of soymilk has about 31 calories, about 3g of protein, about 1.6g of fat and about 5mg of calcium. While every 100g of milk has about 54 calories, about 3.2g or so of protein, 3.2g or so of fat and 104mg or so of calcium.
From the nutritional composition table, milk and soymilk are both rich in nutritional value, of which there is no particularly significant difference in calorie, protein and fat content.
However, the proteins in milk are high-quality animal proteins that are more easily absorbed by the body. Milk is richer in calcium, if you need to supplement calcium, you can choose to drink more milk. Soy milk is richer in lecithin and is also a drink with some nutritional value.