Objective To evaluate the diagnostic value of 99Tcm-methoxy isobutyl isonitrile (MIBI) dual-time imaging for parathyroid adenoma (PA) and parathyroid hyperplasia (PH).Methods Clinical data of 187 patients with pathologically confirmed hyperparathyroidism (HPT) who admitted to the First Affiliated Hospital of Xi’an Jiaotong University School of Medicine from July 2011 to December 2018 were retrospectively collected. Taking postoperative pathology as the standard, the diagnostic value of preoperative 99Tcm-MIBI dual-time imaging was analyzed.Results The serum PTH level of PH patients was higher than that of PA patients (Z=–3.23, P<0.01). Te/N (T: focal area radioactive count, N: the normal tissue radioactivity count of the corresponding thyroid gland on the opposite side of the lesion) in PA and PH patients were lower than Td/N (Z=–3.61, P<0.01; Z=–3.47, P<0.01). The positive rates of 99Tcm-MIBI dual-time imaging in the diagnosis of PA and PH lesions were 67.9% (36/53) and 20.6% (86/418), respectively, and the positive rate of PA were higher (χ2=52.51, P<0.01). The positive rate of 99Tcm-MIBI dual-time imaging in the diagnosis of PA and PH single lesions was higher than that of multiple lesions (P<0.01).Conclusions 99Tcm-MIBI dual-time imaging shows a higher positive rate for PA and a lower positive rate for PH. When HPT is clinically suspected, but 99Tcm-MIBI dual-time imaging is negative and serum PTH is positive, PH should be considered, and B ultrasound and other examinations should be performed to determine the lesion site.