Abstract: Human milk is a biological fluid with complicated components. The quality of human milk is adaptable to the needs of the offspring. It has a direct impact on their body developments. Human milk composition consists of three major nutrients (proteins, fats and carbohydrates), minerals (micronutrients) and vitamins and numerous biological active substance. The advanced research found that the structure human α-lactalbumin made lethal to tumor cells (HAMLET) has a function as the cancer cells killer, and milk fat globule membrane (MFGM) plays an important role in the developments of immune system and intestinal health of the infants, which improves the essential and irreplaceable quality of the human milk. Present studies of components of maternal milk will help to provide the basis for breastfeeding and evidence for guidance and future research.