To the safety evaluation of the caisson type berthing breakwater structure under earthquake action,this paper establishes a two-dimensional computational model of the caisson type berthing breakwater based on the finite element method and the generalized elastoplastic constitutive algorithm,which considering sand liquefaction mode.Numerical simulation research on the time history dynamic response of the structure under earthquake wave action is carried out,and the safety of the structure is evaluated based on the calculation results.The research results indicate that under the frequent encountered earthquake action with a peak acceleration value of 0.1g,the maximum horizontal and vertical acceleration amplification factor of the caisson type berthing breakwater structure is about 1.6,which conforms to the general law of seismic wave propagation in layered soil.Under frequent encountered seismic action,the overall anti-sliding safety factor of the breakwater and the most unfavorable anti-tilting and anti-sliding stability factors of the main components caisson are both greater than the design standards.Under rare encountered earthquakes with a peak acceleration value of 0.2g,the generalized elastoplastic constitutive model can accurately simulate the process of pore water pressure increase and liquefaction resistance safety factor decrease in the fine sand layer of the foundation during earthquakes.On this basis,the calculation model can accurately evaluate the cumulative deformation of the caisson type berthing breakwater under earthquake action,thereby fully demonstrating the reliability of the breakwater structure under rare encountered earthquakes.