This paper presents a non-invasive approach to measuring the instantaneous arterial blood pressure based upon the tissue control method. According to animal experiments, there exists a pressed location where the mean blood pressure in the artery is equivalent to the mean pressure measured on the skin. At this location, the stiffness measured on the skin is equivalent to the stiffness of the tissue only. By means of the tissue control method, the pulsations of the artery are excluded from tissues. The displacement measured on the skin and the tracking pressure obtained from the controller identify the dynamical impedance of the blood vessel, and then estimate the instantaneous intra-arterial blood pressure. The experimental results show that errors of mean blood pressure, systolic blood pressure and diastolic blood pressure are less than 4%, and indicate that the tissue control method is a feasible way to detect the instantaneous arterial blood pressure.