Abstract: Primary megaureter is an idiopathic disease with ureter diameter >7 mm due to structural or functional dysfunction of ureterovesical junction.Currently the underlying pathogenesis of primary megaureter has remained elusive.It is probably related to various disorders of ureter muscle structure.Most patients recover spontaneously.However, for those with severe renal function injury or complicated infection, active surgical intervention is required for averting further deterioration of renal function.This review summarized the pathogenesis, diagnosis and treatment of primary megaureters.