Abstract: Temperature changes which affects the acoustic characteristics of marine sediment is a very important factor. The coaxial differential distance attenuation measurement method is applied on measuring the seafloor sediment acoustic characteristics at different temperatures in this article. As the temperature increasing , some conclusions of acoustic characteristics of marine sediment could be draw: 1) sediment sound velocity changes slowly with obvious fluctuation , but the overall trend of decline is nearly in linear; 2) decay amplitude has been falling in a linear amplitude attenuation downward trend with some volatility outliers; 3) attenuation coefficient shows parabolic-like trend, with strong nonlinearity. As a special type, the speed of sound decreasing with increasing temperature requires further theoretical and experimental study to explain the causes.

Key words: seafloor sediment;acoustic velocity;acoustic attenuation, temperature