[Objectives] The dynamic stability of large ocean-gong passenger vessel is of great important to ensuring the safety of a large number of passengers. It is necessary to carry out vulnerability assessment and optimization for typical failure modes.[Methods] This research adopts assessment method and criteria of parametric rolling, pure loss of stability and excessive acceleration that develop by the International Maritime Organization’s (IMO) 2nd generation Intact Stability criterion. For the first time, the vulnerability assessment of dynamic stability failure modes was conducted for the design scheme of large ocean-gong passenger ship project. In order to fulfil the requirement of of this project, optimization scheme was studied and proposed for this design for the practical point of view.[Results] Basically, the results show that the original design of this ship is not vulnerable to the evaluated dynamic stability failure modes except the pure loss of stability failure mode without considering the speed limit, that means the safety level can meet the requirement. However, the original design can not fulfil the requirements of pure loss of stability criterion, if the service speed is desired to be increased to 24.8 knots. Targeted optimization studies show that, by slightly adjusting design of hull and windows to improve the reserve buoyancy, the safety level of pure loss of stability failure mode can be effectively increased and the limit of service speed is not necessary anymore.[Conclusions] The design scheme of large ocean-going passenger vessel has a high safety margin of dynamic stability, and criteria requirements of dynamic stability failure modes such as parametric rolling, pure loss of stability and excessive acceleration can be satisfied after assessment and proper optimization. The optimization measures can effectively improve the safety level of pure loss of stability and eliminate the service speed limit by means of low cost and small increase in reserve buoyancy. On the whole, the existing design scheme can fully ensure the dynamic stability in the waves of ship while sailing in serious sea conditions and keep the ship safe.