In this study, the complete design process of a metal rubber isolator using a numerical method applied in automobile underwater gliders (AUGs) is researched. A ring-like metal rubber isolator that has the potential to reduce the vibration of the AUGs is proposed. In the numerical design method, the equivalent cantilever beam model is used to identify the mechanical properties of the metal rubber isolator, whose accuracy is verified by experiment. The static stiffness and dynamic stiffness are gained through a fitting method, considering different mass loadings. Different material parameters of a metal rubber isolator, such as relative densities, wire diameters, wire spiral pitch diameters, and mass loading from the power system, greatly influence the mechanical properties and stiffness characteristic. The vibration isolation performance of a metal rubber isolator applied in the AUG is evaluated by a nonlinear single degree of freedom dynamic model, which is solved by the harmonic balance method. The linear stiffness component of the metal rubber isolator is the main influence factor for the vibration isolation performance. The nonlinear stiffness component could shift the isolation frequency.