Based on the propagation theory of elastic waves in unsaturated porous media and single-phase elastic media， considering that a composite multilayer wave impeding block（WIB） with a certain thickness is set in unsaturated soil （composite multilayer wave impeding block with 3 layers as an example）， and using Helmholtz vector decomposition theorem， the analytical solutions of transmitted/reflected amplitude ratio of P1-wave passing through composite multilayer wave impeding block in unsaturated soil are derived. The influences of physical and mechanical parameters such as shear modulus and density of interlayer wave impeding block on the propagation characteristics of P1-wave passing through composite multilayer wave impeding block in unsaturated soil are analyzed by numerical examples. The results show that the shear modulus of interlayer wave impeding block material has a significant influence on the transmission/reflection coefficient， and the density of interlayer wave impeding block material has little influence on the transmission/reflection coefficient. Therefore， strictly controlling the shear modulus of interlayer wave impeding block can obtain better vibration isolation performance， which provides a design criterion for the application of composite multilayer wave impeding block in the field of foundation vibration control.