To improve working stability of inertial navigation system in complex mechanic environment, optimization on shock-isolation for the system was operated under several constrained conditions by using particle swarm optimization method (PSOM). In this research, the system was simplified as six-degree vibration system model which was certified by comparing its results and those from finite element model. Then, the most optimal result was obtained rapidly and efficiently in the process of parallel research. Furthermore, optimal parameters were concluded and some useful conclusions were presented as follow: the low shore hardness rubber materials, great height and little difference between inner and outer radius of rubber isolators are preferred whenrequired strength is achieved.