OBJECTIVE To investigate the causes of misdiagnosis and the surgical treatment of primary hyperparathyroidism (PHPT). METHODS The clinical data of 26 patients with PHPT from July 2008 to January 2013 in The Affiliated Hospital of Chengde Medical College and The Fourth Hospital of Hebei Medical University were retrospectively analyzed, including preoperative diagnosis and operative method. The level of serum calciumion and serum parathyroid hormone (PTH), Ultrasonography, CT, (99)mTc-methoxy isobutylis onitrile ((99)mTc-MIBI) were used in the diagnosis before operation. All patients accepted surgical treatment after the level of serum calciumion decreased to normal. RESULTS The level of PTH was examined 10 min after resection, which declined more than 50%. After pathological examination, 23 cases were diagnosed as parathyroid adenoma, 2 cases were parathyroid hyperplasia, and 1 case was parathyroid carcinoma. The level of serum calciumion and serum parathyroid hormone were returned to the normal level after operation. All patients recovered with no postoperative complication.Followed up lasted from 6 months to 5 years, no case recurred.Sixteen cases with symptoms experienced significant improvement in signs, including 10 cases with clinical symptoms completely disappeared. CONCLUSIONS The test of serum calciumion and serum PTH, Ultrasonography, CT, (99)mTc-MIBI are helpful to reduce the misdiagnose rate of primary hyperparathyroidism before operation. The examination of serum parathyroid hormone in operation is helpful to reduce the operation range and time.