Objective：To investigate the clinical value of 99mTc-HYNIC-TOC whole-body scintigraphy and single photon emission com－puted tomography/computed tomography（SPECT/CT） in the diagnosis of adrenal pheochromocytoma. Methods：A total of 83 patients suspected of adrenal pheochromocytoma were enrolled and underwent both 99mTc-HYNIC-TOC whole-body scintigraphy and SPECT/CT. The findings of 99mTc-HYNIC-TOC whole-body scintigraphy and SPECT/CT were compared with pathological results. Results：Of all 83 patients，19 obtained positive results of 99mTc-HYNIC-TOC whole-body scintigraphy，among whom 17 had pathologically confirmed pheochromocytoma；among the 64 patients with negative results on whole-body scintigraphy，24 had pathologically con－firmed pheochromocytoma. Among the 56 patients with positive results of SPECT/CT，38 had pathologically confirmed pheochromocy－toma；among the 27 patients with negative results of SPECT/CT，3 had pathologically confirmed pheochromocytoma. In the diagnosis of adrenal pheochromocytoma，99mTc-HYNIC-TOC whole-body scintigraphy had a sensitivity of 41.5%，a specificity of 95.2%，an accu－racy of 68.7%，a positive predictive value of 89.5%，and a negative predictive value of 62.5%，while SPECT/CT had a sensitivity of 92.7%，a specificity of 57.1%，an accuracy of 74.7%，a positive predictive value of 67.9%，and a negative predictive value of 88.9%. The receiver operating characteristic（ROC） curve of the long di－ameter of adrenal pheochromocytoma measured by 99mTc-HYN－IC-TOC whole-body scintigraphy showed that the long diameter of adrenal pheochromocytoma had an area under the ROC curve of 0.735（95% confidence interval：0.578-0.892，P=0.011） at the cut-off value of 4.0 cm，with a sensitivity of 76.5% and a specificity of 75.0% in diagnosis. Conclusion：Compared with 99mTc-HYNIC-TOC whole-body scintigraphy，SPECT/CT had higher accuracy，sensitivity，and negative predictive value in the diagnosis of adrenal pheochromocytoma，as well as a higher detection rate of tumor with a relatively short long diameter or solid-cystic lesions.