Frequent outbreaks of marine disasters in the context of global warming pose a serious threat to the sustainable development of coastal areas and the construction of global maritime capitals. Implementing integrated marine and coastal management and assessing and enhancing cities’ resilience to marine disasters are of practical importance. Based on the capital perspective, this study innovatively constructed a framework for the Coastal Marine Disaster Resilience Index (CMDRI) for the coastal city level, considering the main marine disaster characteristics of Chinese coastal areas. Eight coastal cities in China proposed to build global maritime capitals were used as research objects. The random forest model, which can handle complex nonlinear systems and feature importance, was applied for the first time to resilience assessment and key factor identification in marine disasters. The results show that the overall level of CMDRI of each city is steadily increasing, with Shenzhen having the highest marine disaster resilience grade for each year and Zhoushan having the lowest. Economic and human capitals accounted for a more significant proportion of key factors, followed by physical and social capitals, and environmental capital accounted for a minor proportion. The comparison results of model performance show that the random forest model has better fitting accuracy and stability in assessing CMDRI and can be further applied to other disaster resilience and sustainability areas. © 2022 by the authors.