BACKGROUND: Primary hyperparathyroidism (PHPT) is a disease caused by excessive secretion of parathyroid hormone (PTH) due to parathyroid gland lesions, resulting in high serum calcium and low phosphorus, leading to symptoms such as digestive ulcers and urinary tract stones. METHODS: We report a case of multiple urinary tract stones with high serum calcium and low serum phosphorus. Upon investigation, it was found that the cause was primary hyperparathyroidism. RESULTS: The serum PTH level of the patient was detected to be significantly elevated. At the same time, neck ultra-sound showed the presence of a parathyroid adenoma. Therefore, it is believed that the patient has PHPT causing high serum calcium and low serum phosphorus, leading to multiple urinary tract stones. CONCLUSIONS: When patients with urinary tract stones have high serum calcium levels and low serum phosphorus levels, laboratory personnel should consider the possibility of PHPT. Simultaneously measuring PTH levels and promptly reminding clinical doctors to perform parathyroid ultrasound and other examinations on patients to reduce the possibility of a missed PHPT diagnosis.