Abstract: In view of the complex structure form and changeable environmental load of jacket structure dolphin in port engineering, this paper simplifies it to a space-rigid frame structure and determines the main failure components and failure paths based on β-unzipping method. The failure characteristics and system reliability index of jacket structure dolphin are obtained. In order to improve the reliability analysis efficiency of complex rigid frame structure system, an artificial neural network combined with Monte Carlo method is proposed to determine the relationship between structure responses and environmental loads, and then to determine the ultimate state equation of a structure. The failure of the whole structure is obtained. The results show that the reliability analysis of complex rigid frame structures based on β-unzipping method is of great importance in determining the weak components and failure characteristics of the structures. The neural network combined with Monte Carlo method can obviously improve the computational efficiency and can be applied to the reliability analysis of more complex marine structures. The results are of a great significance to the risk assessment and safety design of marine and coastal engineering structures.