Objective To compare the role on determining the functional location of primary hyperaldosteronism (PHA)by multi-slice spiral CT (MSCT)and by adrenal vein sampling (AVS), and to discuss the reasonable method to use MSCT and AVS in localization diagnosis of PHA. Methods Clinical data of 78 patients with PHA were analyzed retrospectively. These patients were diagnosed in our department from June 2014 to June 2018. There were 27 male and 51 female patients. With mean age of (47.5±11.2)years old. The mean systolic blood pressure was(190±24)mmHg and mean diastolic blood pressure was (111±16)mmHg. The mean history of hypertension was (6.0±6.0)years. The mean serum potassium was (2.4±0.6)mmol/L. The mean plasma aldosterone concentration(PAC) was (415.7±235.4)pg/ml. The mean plasma renin activity(PRA) was (3.2±5.7)ng/(ml·h). The mean aldosterone/renin ratio(ARR) was 409.0±434.9. All PHA patients underwent MSCT and AVS, the accuracy on determining the functional location of PHA by MSCT and by AVS were evaluated based on the pathological results and clinical outcomes. The influence of adrenal size and character on the accuracy of determining the functional location of PHA by MSCT were analyzed. Results The rate of accuracy of determining the location of PHA by AVS was higher than that by MSCT[100.0%(78/78)vs. 71.8%(56/78), P 2 cm, the rate of accuracy in localization diagnosis with MSCT was 50.0%(4/8), 81.0%(17/21), 92.9%(26/28), 100.0%(9/9) respectively. Its trend has statistical significance (P 0.05). Conclusions AVS is the gold standard for localization diagnosis. When MSCT indicates that there is no obvious abnormality in the adrenal gland, adrenal hyperplasia, small tumor(≤2 cm), and bilateral adrenal lesions, AVS should be examined at the same time, which can be considered as the gold standard for localization diagnosis. For isolated adrenal tumor (>2 cm) in PHA, the accuracy of localization diagnosis in MSCT is very high and the AVS is unnecessary. Key words: Primary hyperaldosteronism; Multi-slice spiral CT; Adrenal vein sampling; Localization diagnosis