Renal tubular acidosis (RTA) is a metabolic acidosis caused by congenital genetic defects and various secondary factors, resulting in the reabsorption of sodium bicarbonate in the proximal tubules or/and the dysfunction of acid excretion in the distal tubules. The main manifestations are: ① hyperchloremic, normal anion gap (AG) metabolic acidosis; ② electrolyte disorders; ③ bone disease; ④ urinary tract symptoms. Most patients do not have glomerular abnormalities. In some genetic diseases, RTA may be the main or only clinical manifestation. This group of diseases is divided into primary and secondary according to the cause; divided into complete and incomplete according to whether systemic metabolic acidosis occurs; and divided into proximal and distal RTA according to the main site of renal tubular involvement. At present, a comprehensive classification based on the site of lesions, pathophysiological changes and clinical manifestations is often used: type 1, distal RTA; type 2, proximal RTA; type 3, with the characteristics of both type 1 and type 2 RTA; type 4, hyperkalemic RTA.