There are various causes of pyeloureteral stones, commonly including metabolic abnormalities, local factors, drug factors and so on. 1. Abnormal metabolism, mainly refers to the increase of some substances that form urinary stones, such as calcium, oxalic acid, uric acid or cystine and other substances in the urine; can also be seen in the change of urinary pH, the urine volume is reduced and other situations. 2. Local factors, urinary tract obstruction, infection, and the presence of foreign bodies in the urinary tract are common local causes of stones, especially the renal ureteral junction of narrowing and deformity. 3. Drug-related factors, which are relatively rare, are mostly found in two types of drugs, one is drugs with high concentration in urine but low solubility, such as aminopterin, and the other is drugs inducing the formation of stones, such as acetazolamide, vitamin D or C, and so on. It is recommended to actively seek medical attention to clarify the cause of the disease and provide targeted treatment.