It has different fat content, different nutritional value, different calories, and is suitable for different people.

1. Different fat content: Whole milk contains higher fat content, while pure milk contains lower fat content.

2. Different nutritional values: Whole milk is rich in protein, vitamins, minerals and other nutrients, while pure milk is rich in protein, calcium, vitamins and other nutrients.

3. Different calories: Whole milk contains more calories. The fat content is reduced during the skimming process, so the calories in pure milk are relatively low.

4. Suitable for different groups of people: Whole milk is more suitable for athletes, fitness people, the elderly and other people, while pure milk is more suitable for most people, especially people with calcium deficiency.