Abstract: In mock circulatory systems, the aortic flow is of violent pulsation. Measuring this signal directly with flow meter will limit its applications to mimic different physiological objects, considering the effects of diameter and wall thickness of the tube, the measurement range of flow meters, etc. In order to solve these problems, an indirect method using pressure signal to estimate the pulsatile flow was proposed. The mock circulatory system is first modeled with different Windkessel models. Then the aortic pressure and arterial pressure are considered as the input and observation variable, respectively, to estimate model parameters and aortic flow based on the extended Kalman filter (EKF). The accuracy of flow estimation is evaluated by the root mean square error index. The experimental results show that the fourelement Windkessel model can describe the dynamic performance of the mock circulation system and thus estimate the aortic flow. This paper provides a novel method to measure the aortic flow in testing and evaluating cardiovascular devices. Key words：

Key words: mock circulatory system (MCS), Windkessel model, aortic flow, soft measurement, extended Kalman filter (EKF)