The effects of different pressures and temperatures on the static and dynamic behavior of the carbon black filled SBR nanocomposites were studied by molecular dynamics simulation. The results show that the glass transition temperature of the composites increases linearly with the external pressure. In addition, both the free volume and the molecular chain size of the systems decrease with the increase of pressure or the decrease of temperature, which also lead to the decrease of the translational diffusion and rotational dynamics of the molecular chains. By calculating the storage modulus, loss modulus and loss factor of materials, it is found that both the storage modulus and loss modulus of materials increase with the increase of pressure or the decrease of temperature, while the loss factor of materials decreases with the increase of pressure or the decrease of temperature. These results provide a microscopic mechanism for understanding the performance evolution of underwater acoustic materials within a large pressure and wide temperature range.