Objective To compare some lumped - parameter models often used in simulating input impedance in systemic circulation, and apply the results to heart failure and hypertension. Methods Some methods and criterions, which can ensure the precision in simulation, were introduced to obtain the model parameters with the least square method. Results The precision of Bruttini&Gnudi four - element model and Liu ZR modified five - element model in simulation were better than other models. Physiological facts in heart failure and hypertension were well reflected by these two models. Conclusion Four - element model and modified five - element model are relatively applicable lumped - parameter models.