Blood pressure (BP) is one of the most frequently measured bio-signals, and the automatic BP monitor that measures the BP is usually based on the oscillometric method where the pulse along the blood vessel is recorded as a pressure oscillation inside the air cuff. The correlation between oscillometric signal and the upper limb’s bio-mechanical parameters such as radius, thickness, and elasticity of brachial artery, and elasticity of soft tissue is studied to assess the possibility of extracting health condition of humans other than BP during BP measurement. The parametric study is conducted with a simple finite element method (FEM) model containing bone, soft tissue, and the artery to identify the bio-mechanical parameters that affect the amplitude of the oscillometric signal. The result shows that the inner radius of the brachial artery is the most influential parameter on the oscillometric signal. The correlation between oscillometric signal and the inner radius of the brachial artery is also verified by the experiment with the cardiovascular dynamic simulator fabricated by this group [1,2]. The blood pressure waveform generated by the simulator produces the pulse and this is fed into the upper limb phantom to mimic the blood pressure measuring situation. Using series of phantoms with the various artery inner radius, the oscillometric signals are acquired with a commercial automatic BP monitor to evaluate the correlation between the inner radius of the brachial artery and the oscillometric signal. The amplitude variation of the oscillometric signal is also observed from the actual human arm when the vessel vasodilation is induced. The correlation between oscillometric signal and the parameters of the brachial artery shows the possibility of extracting the vessel-related information from the oscillometric signal during BP measurement.