The paper presents the results of centrifuge model tests performed to study the failure mechanism of suction bucket foundation of offshore platform under cyclic lateral vibration loads. Electromagnetic actuator with wide frequency range and heavy load used in the tests was developed in light of China’s offshore geological conditions and ocean environments. Two failure modes might happen: liquefaction in the early excitation and settlement-induced problem after long-term excitation. However, with increased stiffness of the large diameter cylinders, the pore pressures and the induced settlement decrease. A three dimensional limit analysis method by which the joint effect of lateral load, horizontal load and bending moment could be considered was proposed based on upper boundary theorem of plastic mechanics to simulate the soil-foundation system. The results of numerical analysis were basically in agreement with the centrifuge modeling results.