Angiotensin converting enzyme (ACE) plays a pivotal role in blood pressure regulation, and its interaction with an ACE inhibitor (ACEI) is an important research topic for treatment of hypertension. Herein, a low reagent consumption, multiparameter and highly sensitive quartz crystal microbalance (QCM) at 35-MHz fundamental frequency was utilized to monitor in situ the binding process of solution lisinopril (LIS, a carboxylic third-generation ACEI) to ACE adsorbed at a 1-dodecanethiol (C12SH)-modified Au electrode. From the QCM data, the binding molar ratio ( r) of LIS to adsorbed ACE was estimated to be 2.3:1, and the binding and dissociation rate constants ( k 1 and k −1) and the binding equilibrium constant ( K a) were estimated to be k 1 = 4.1 × 10 6 L mol −1 s −1, k −1 = 7.3 × 10 −3 s −1 and K a = 5.62 × 10 8 L mol −1, respectively. Comparable qualitative and quantitative results were also obtained from separate experiments of cyclic voltammetry, electrochemical impedance spectroscopy and surface plasmon resonance measurements.