Traditionally only the transmission of the radial displacement wave used to be emphasized in the theories that analyse the transmission of the pulse wave in the elastic tube.To understand the behavior of the axial displacement wave in the elastic tube,especially,in the arteries,this context analysing the transmission of the axial displacement wave in the elastic tube,and comparison being made with the radial displacement wave in wave velocity and wave damping in the physiologic range,and in quantities describing the effect of these waves on the cardiovascular system.The result shows that,on most conditions and in most arteries,the axial displacement wave exerts much less influence on the cardiovascular system than the radial displacement wave,so it can be omitted;but on some special conditions,the axial displacememt wave is as important as the radial displacement wave.