Background Adrenal tumors, including benign cortical adenoma (BCA) and pheochromocytoma (PCC) or paraganglioma (PGL), have been more frequently detected during imaging examinations in recent years. However, the associated clinical or laboratory characteristics, especially on the Chinese population, still need to be investigated. Methods We conducted a retrospective analysis of 491 patients pathologically diagnosed with adrenal tumors, from Jan 19, 2018 to Dec 17, 2019, at a tertiary referral hospital in Wuhan of China. Our findings including 247 (50.3%) BCA cases, and 92 (18.7) PCC/PGL cases and other cases. Both the clinical and laboratory parameters were reviewed and analyzed. Results Compared with other adrenal tumors, PCC/PGL showed larger tumor diameters and more frequently located on the right side, and were with higher levels of urinary catecholoamines and plasma metanephrines, especially for the 24 h urinary vanilmandelic acid (VMA) and plasma normetanephrine (NMN). The optimal diagnostic thresholds were 29.40 ug/24 h for VMA (sensitivity, 85%; specificity, 91%) and 0.63 nmol/L for NMN (sensitivity, 91%; specificity, 92%). The 24 h urinary VMA and plasma NMN also shared abilities to differentiate between different tumor laterality and different tumor size in PCC/PGL cases. In addition, compared with the other benign tumors, BCA were smaller in diameters (20 vs 35 mm, p < 0.001), and seemed to be lower in levels of plasma epinephrine, dopamine and serum ACTH. Conclusion 24 h Urinary catecholoamines and plasma metanephrines, especially for the 24 h urinary VMA and plasma MNM, showed higher diagnostic efficacies for PCC/PGL, and were tightly associated with the tumor laterality and tumor size.