The objectification and quantification of pulse diagnosis is one of the important research subjects of traditional Chinese medicine (TCM) modernization. Following the holism concept of TCM, the pulse wave system is considered as an entire system of life energy propagating within the blood in the form of wave, and a corresponding mechanics model is then established. The method of inverse analysis in the wave propagation theory in mechanics is generalized to deal with the pulse wave signals. Once the form of pulse wave, e.g. the pressure wave, is measured, the constitutive equation of the system as well as other forms of pulse wave such as the particle velocity wave, the specific volume wave and the internal energy wave can be deduced. It is indicated that a pulse phenomenon includes both the blood flow and the energy wave propagating within the blood. The former is a visible mass-flow with lower velocity, while the latter is an invisible energy-flow with much higher velocity, regarded respectively to the "blood" and the "Qi" in TCM. The propagating characters of pulse wave are mainly determined by the constitutive equation of the system which may correspond to the "body constitution" in TCM. Some intrinsic relationships may exist between them, and should be further investigated. Moreover, the effects of the non-linearity and the viscosity of the constitutive equation on the pulse wave characters are preliminarily discussed.