Lipids (Lipid) is a general term for neutral fats, lipids and their derivatives, their common physical properties are insoluble in water, soluble in organic solvents (such as ethanol, ether, etc.), there are two main types of fat in the human body: 1, storage fats, such as neutral fats, mainly located in the subcutaneous, kidneys, pancreas and other parts of the body; 2, structural fats, such as lipids (phospholipids, glycolipids, cholesterol, etc.), mainly located in the cell, the Phospholipids (phospholipid) consists of glycerol, fatty acids and nitrogen-containing bases, is the main component of cell membranes and intracellular membrane structure, phospholipids in the brain, nervous tissue, bone marrow and liver and other tissues in the content of the larger, phospholipids can be divided into lecithin, ceruloplasmin and nerve sheath phospholipids of the three kinds of phospholipids, show that phospholipids commonly used methods of acidic hematoxylin red method, pyridine extraction method.