Achievement of a mean blood pressure (MBP) target is one of the hemodynamic goals to ensure an adequate blood perfusion pressure in critically ill patients. Arterial catheter allows for a continuous and precise monitoring of arterial pressure signal. In addition to giving a precise MBP monitoring, analysis of the blood pressure wave provides information that may help the clinician to interpret hemodynamic status. The interpretation of BP wave requires the understanding of simple principles. In this review, we first discuss the physiological mechanism responsible for arterial pressure generation. We then emphasize the interpretation of the static indexes and the dynamic indexes generated by heart–lung interactions derived from arterial pressure wave. Finally, we focus on MBP value as a therapeutic target in critically ill patients. We discuss the recommended target MBP value by reviewing available data from experimental and clinical studies.