In random marine environment, ships and offshore platforms need to bear external hydrodynamic forces, resulting in structural stress response in floating structures. Due to the strong randomness of sea conditions, fatal damage and overturning of platforms and ships may occur in extreme cases. Based on the principle of probability and statistics and considering the uncertainty of sea conditions and structural manufacturing, the research group has established a reliability analysis method that can consider random wave load, structural ultimate bearing capacity and fatigue damage, which has been applied to the safety evaluation of container ships and semi submersible platforms.