Abstract: Attenuation was paid to the study on the sound absorption mechanism of water-soluble polymer during dissolving.A specially designed water-soluble polymer coating was synthesized in our lab.The sound attenuation property was measured in sound tube.Result showed that the sound attenuation of the gradient polymer solution was larger than that of the uniform.Depending on the experimental result and the theory of sound wave propagation in layered medium,a mechanism of gradient water-soluble polymer solution was developed.This mechanism can be described as follows:a water-soluble polymer coating formed a concentration gradient layer when it was dissolved in water.This gradient layer ted to multiple reflection and absorption of sound.Finally the sound energy was transferred into heat.