Abstract: Arterial Pulse Wave Velocity（PWV） measurement is of great theoretical importance and practical value in evaluating the arterial elasticity and stiffness.To improve the accuracy in PWV measurement in complicated noise backgrounds，the paper sets forth the basic philosophy and specific implementation approaches using a chaotic oscillator measurement system in Duffing equation structure for PWV measurement，and studies the method for determining the start point of pulse waveform trough depending on Lyapunov performance indices and consequently accurately measuring Pulse Transit Time（PTT） and PWV.The experimental result demonstrates that，compared with traditional PWV measurement methods，it features higher antijamming capability and marked repeatability，thereby greatly improving its measuring accuracy.The effectiveness and unique features of this method have been proved by theory and experiments.