Endocytosis is a process through which extracellular materials are transported into cell through membrane deformation. This process is not a simple step-by-step process in which a series of proteins function according to the chronological order, but rather a complex process comprising many members which are regulated precisely. The role of endocytosis is broadly divided into two categories, phagocytosis and pinocytosis, the latter is divided into four species in accordance with the size of endocytosis substances: clathrin dependent endocytosis, the diameter of clathrin-coated vesicle is 100–150 nm; caveolin dependent endocytosis, the diameter of caveolin protein-coated vesicle is 50–100 nm; macropinocytosis, the diameter of macropinocytosis is generally 0.5–2 μm, sometimes up to 5 μm; clathrin and caveolin independent endocytosis. Many proteins including endophilin A1, A2, A3, and endocytotic proteins B, B1a, and B1b as well as dynamin, actin and Rab protein families are involved in endocytosis and play an important role in different stages. The abnormal endocytosis may be involved in the development of certain diseases.