Albumin is a protein within human plasma, and its main roles are: 1. albumin can maintain the colloidal osmotic pressure within the plasma; 2. albumin is a major nutrient in the human body; 3. albumin plays a colloidal protective role for globulin in the body; 4. albumin can ensure the dynamic balance of intracellular fluid, extracellular fluid and intertissue fluid; 5. albumin can form a complex with some small molecules in the body and play a transport role in the blood; 6. it combines with heavy metals in the body and plays a role in reducing the toxicity of heavy metals.