With the research background of underwater non-contact explosion condition,base on the presenting Shockisolation theory and viscoelastic materials mechanical characteristics,the paper analysis the nonlinear problems of shock-isolation structures of viscoelastic composite materials,and the finite element model of shock-isolation structures based on the actual working conditions of physical prototype is built,the dynamical decay curves of shock-isolation structures in the condition of transient excitation is obtained with simulation,and proves the validity of the shock-isolation structures with experiments.