A method for measurement of the dynamic properties of rubber under high hydrostatic pressure by water-filled acoustic tube was proposed based on the simplified analytical expression of equivalent complex wavenumber for wave propagation in the sample with evenly spaced cylindrical tunnel cavities, as well as measurement and solution of this wavenumber in the water-filled acoustic tube. Two types of samples, named the uniform solid structure and the structure with evenly spaced cylindrical tunnel cavities were made. The longitudinal wavenumber and complex equivalent wavenumber for the samples were  obtained and used to calculate the dynamic properties. A piece of rubber was tested under atmospheric pressure and hydrostatic pressure. The influence of hydrostatic pressure was analyzed and error analysis was performed. The absorption coefficients of one acoustic coating under hydrostatic pressure were tested and compared with the simulation results by the finite element method using the measured dynamic properties, which demonstrates that the method can produce accurate results and is a potential method for testing the dynamic properties of rubber under high hydrostatic pressure.