Abstract: The penetration behavior of suction bucket foundations has a significant effect on engineering application. Based on the measured installation data of two suction bucket jacket foundations in an offshore wind farm, the CPT-based method used for calculating the penetration resistance in seabed and the two critical empirical factors, k_\textp(z) and k_\textf(z) , recommended by the DNV code are studied. The component of penetration resistance of suction bucket in clay soil layer and sand soil layer, respectively, and the soil plug during suction penetration process are analyzed. The results show that the penetration resistance of suction bucket can be precisely predicted by the CPT-based method. The empirical factor k_\textf(z) for silty soil, silty clay soil and the empirical factor k_\textp(z) for grit sand, medium-dense sand and coarse sand are overestimated by the DNV code. During suction penetration process, the soil plug of suction bucket foundations relies on the seabed soil layers and mechanical properties of soils.