Uric acid is the end product of purine metabolism and is mainly produced by the enzymatic breakdown of nucleic acids and other purine compounds from cellular metabolism and purines from food. In the human body, 80% of uric acid is produced by endogenous purine metabolism, and 20% comes from purine-rich or nucleic acid protein foods. The saturation and concentration of uric acid in the body at 37℃ is about 420μmol/L (7mg/dl), and above this concentration, hyperuricemia is considered. The body has a self-regulatory function for uric acid to maintain it at a certain stable level. If the endogenous purine production is excessive or the uric acid excretion of the body is reduced, the blood uric acid level will rise, resulting in hyperuricemia. When uric acid exceeds the saturation concentration, urate crystals are precipitated and can be deposited directly in the joints and surrounding soft tissues, renal tubules and blood vessels. Most patients with primary hyperuricemia have no clinical symptoms and often present with a metabolic syndrome. Long-term hyperuricemia may lead to gout and therefore manifest the symptoms of gout. 1, Asymptomatic phase: only fluctuating or persistent hyperuricemia. 2, gouty arthritis: often first in the first metatarsophalangeal joint, or ankle, knee joints, the onset of the disease is rapid, recurrent attacks. 3, gouty stone: the first symptoms appear untreated patients, after many years about 70% can appear gouty stone. 4, renal lesions: mainly manifested in both gouty nephropathy and uric acid kidney stones. 5. Eye lesions: gout stones, recurrent conjunctivitis, keratitis and sclerenitis may appear. Therefore, the saturation and concentration of uric acid in the body at 37℃ is about 420μmol/L (7mg/dl), and above this concentration, it is hyperuricemia.