<p>Offshore platforms operating in complex marine environments, particularly under typhoon conditions, face severe and rapidly evolving risks. To address this issue, this paper proposes a method for risk assessment, visualization and evolution analysis based on a cloud model and Markov Chain Monte Carlo (MCMC). First, an offshore platform risk assessment indicator system is constructed covering four dimensions: personnel, platform, environment and management. The comprehensive weights of these indicators are determined using the FAHP-DEMATEL method. Then, a comprehensive risk assessment and its visualization for offshore platforms is achieved through the cloud model which has advantages in handling risk ambiguity and randomness. Subsequently, the outputs of the cloud model are used as input parameters to the MCMC model to analyze the dynamic risk evolution process of offshore platforms under typhoon disturbances. Finally, the combined methods are applied to a platform in the South China Sea and its calculation results demonstrate that the dynamic risk evolution throughout the entire process of a typhoon’s passage can be effectively assessed and visually displayed. The proposed methods in this paper provide a scientific basis for maritime authorities to formulate efficient safety supervision strategies, such as precise risk control of offshore platforms at different time intervals, which are of great significance for ensuring the safe and stable operation of offshore platforms under typhoon weather.</p>