Objective:To summarize the experience in the primary hyperparathyroidism. Methods:The clinical data of 48 cases of the PHPT admitted from 1991 to 2005 in the First Affiliated Hospital of China Medical University were analyzed retrospectively. Results:For ultrasonography,the positive rate was 81.1%(30/37).For ECT,the positive rate was 91.4%(32/35).Unilateral neck explorations (UNE) was performed in 38 cases with parathyroidoma.Four cases of parathyroid hyperplasia were treated by UNE and the other 2 cases by bilateral neck exploration (BNE).The procedure for 3 cases of parathyroid carcinoma was the same as that for papillary thyroid carcinoma.Unilateral resection of thyroid and parathyroid was done in a case of parathyroidoma with malignant change.All cases developed hypocalcemia in various degrees after operation,but the symptoms were relieved with the use of calcium gluconate. Conclusion:PHPT could be diagnosed according to coelevated calcemia and PTH.Ultrasonography and ECT should be considered as the methods of first choice for preoperative localization.UNE of parathyroidoma could be feasible if accurate image localizations are available.