Objective:To investigate the different clinical behavior and the diagnosis and trearment of primary hyperparathyroidism(PHPT). Methods:Clinical data of 53 patients with PHPT treated in Beijing Jishuitan Hospital from May 1977 to April 2004 were collected and analyzed. Results:53 patients with PHPT were confirmed by operation and pathology. The majority of the patients were aged 20~50 years. There were more female than male patients. There were various clinical manifestations, and the duration of illness was protracted. Many cases were misdiagnosed. There were bone pathologic changes of varying extent in all patients, stones in urinary system plus bone pathology in 11 cases, serum level of calcium was raised in 51 patients(96.2%) and parathyroid hormone (PTH) was elevated in all examined 48 cases. Ultrasound, MIBI and CT were done before operation after 1991, and accurate preoperative localization diagnosis was obtained. Minimally invasive parathyroidectomy (MIP) was successfully completed in 39 of 45 cases, and the primary operation cure rate was 97.4%. At postoperative followup of 10 months to 10 years, with the exception of 15 cases of severe bone deformity that had no obvious improvement, the other symptoms and signs were all relieved to varying extents, the laboratory markers returned to normal, and there was no permanent hypoparathyroidism or recurrent nerve injury or other complications.Conclusions:Early diagnosis of PHPT and effective early treatment by surgical removal of the pathologic lesion can alleviate the occurrence of severe bone changes and deformity. The preoperative combined use of imaging localization technique and overall assessment can improve the accuracy of diagnostic localization of the lesion.