Abstract: Aim\ To determine the intracellular pH and calcium ion in patients with essential hypertension.\ Methods\ Sixty cases of essential hypertension was recruited to enroll the study.\ The lymphocytes of the patients was isolated and washed with non HCO 3 washing water.\ Results\ It was demonstrated the pH in pretreated EH patients was markedly lower than in controls, while Ca 2+ i in EH patients was higher.\ A negative correlationship between pHi and blood pressure（ r=-0 86,P ＜0 001） was demonstrated.\ Conclusion\ That trans membrance proton transport（especially Ca 2+ /H + exchange） might hold potential role in regulating vascular tone and pHi in EH patients.