The study was conducted to investigate how changes in the internal compliance and stiffness of the blood vessels affect the changes in blood pressure and systolic peak time using the RLC Windkessel Model, a secondary blood vessel model of the brachial artery. For this purpose, each component coefficient for blood pressure waveforms of people before and after surgery and before and after drug treatment was estimated. And the expression time of systolic peak time was measured when the elastic value that can affect the change of the waveform of blood pressure change was changed, and the relationship between elasticity and systolic peak time was derived by regression method. It was confirmed that elasticity was affected by the peak time of systolic period, but it did not affect the size of blood pressure. The study was conducted to determine how inertance affects blood pressure, and blood pressure pulse wave was measured before and after heart transplant, and blood pressure pulse wave was measured before and after medication. R, L, and C components of Windkessel models were estimated in blood pressure waveforms. The factors that affect the increase of blood pressure and the decrease of systolic peak time were due to the increase of L component in the RLC component.