The kidney unit is mainly composed of the renal tubules and the renal corpuscles, and the human kidney consists of more than one million kidney units. The function of the glomerulus is mainly filtration. When the glomerular structure changes, such as endothelial swelling, epithelial cell fusion or basement membrane fracture, some beneficial components, such as protein, may be filtered out of the glomerulus or the structure changes, so that metabolites are retained in the body, which can be caused by renal insufficiency. Another function of renal tubules is the reabsorption function, some small molecules of protein or beneficial sugars, amino acids, electrolytes, sometimes can be reabsorbed through the proximal and distal tubules of the renal tubules, at the same time, the proximal and distal tubules, there is also a very important function of the human body, that is, the regulation of acid-base balance. In addition, there is also the concentration and dilution function to regulate water metabolism. In a word, the function of kidney mainly depends on the structure of kidney unit to play a role, when the structure of kidney unit is changed, a series of clinical pathological conditions and pathological phenomena will occur.