Abstract: Exploring the stability of ring-stiffened cylindrical shells under hydrostatic pressure is of highly importance for the deep-sea engineering. For the influences of mechanical properties on the stability of ring-stiffened cylindrical shells, two kinds of materials, high-strength steel and titanium alloy were chosen and the typical structural model was established in this paper. By combing the finite element calculation and theoretical analyses, the effects laws of pivotal material performance properties parameters on the instability critical pressure and mode of ring-stiffened cylindrical shells under hydrostatic pressure were mainly studied, such as Young's modulus, yield strength and hardening capacity. This work could provide a reliable basis for the optimal design and the increase of carrying capacity of ring-stiffened cylindrical shells.