Abstract Background To investigate the features of 24-hour urine and paired serum electrolytes in hypertensive patients with primary aldosteronism (PA). Methods A total of 764 hypertensive patients, who underwent PA screening and completed the measurement of 24-hour urine and paired serum electrolytes from January 2009 to January 2014 at the Hypertension Center of People’s Hospital of Xinjiang Uygur Autonomous Region, were included. Of which, 135 patients were diagnosed with PA, whereas 629 patients were non-PA patients. Results Compared with the non-PA group, serum potassium (3.66 ± 0.41 vs. 3.86 ± 0.37 mmol/L), serum phosphorus (1.08 ± 0.16 vs. 1.16 ± 0.19 mmol/L), and calcium–phosphorus product (29.7 ± 5.2 vs. 32.4 ± 6.9 mg2/dL2) were lower in the PA group, while urine potassium (41.5, 31.6–52.4 vs. 35.9, 27.7–46.3 mmol/L), urine calcium (6.0, 4.5–8.1 vs. 5.2, 3.9–6.9 mmol/L), urine magnesium (3.8, 3.1–5.0 vs. 3.5, 2.7–4.6 mmol/L), the ratio of blood sodium to urine sodium divided by the ratio of blood potassium squared to urine potassium (SUSPPUP) (2.48, 1.71–3.95 vs. 1.96, 1.39–2.73) were higher in PA group (P < 0.01). Hypokalemia, hypocalcemia, urinary potassium > 54.1 mmol/L, urinary calcium > 7.5 mmol/L, and calcium–phosphorus product < 35 mg2/dL2 were more frequently observed in PA patients (P < 0.05). Conclusions In addition to hypokalemia and hypocalcemia, hypertensive patients with PA have higher urinary potassium, magnesium, calcium excretion but lower serum phosphorus. Their electrolyte characteristics show a higher SUSPPUP ratio and a lower calcium–phosphorus product.