Abstract: Emphasis of this work was paid to the study on the sound absorption mechanism of gradient polymer solution. A specially designed gradient polymer solution and an uniform polymer solution were synthesized. The sound attenuation properties of the gradient polymer solution and the uniform polymer solution were measured in sound tube. Results show that the sound attenuation of the gradient polymer solution is larger than that of the uniform. Depending on the experimental result and the theory of sound wave propagation in layered medium, a mathematical model of sound attenuation in the gradient polymer solution was established. And a calculating program was carried out by Maple and Matlab. The calculated results are fairly in good agreement with the measured. So mechanism of the gradient polymer solution was developed. This mechanism can be described as follows: a polymer solution with the concentration gradient layer forms the gradient polymer solution. This gradient layer led to multiple reflection and absorption of sound when the sound wave propagated in it. Finally the sound energy was transferred into heat.