Abstract: As a new type of offshore foundation,the suction bucket foundation has been widely applied to soft ground in beach-shallow water.The response of the suction bucket foundation subjected to combined loads is therefore of significant importance for the design and construction of offshore foundation.Based on the Mohr-Coulomb yield criterion,a perfect elasto-plastic finite element method for numerical assessment of bearing capacity of bucket foundation under the combined loads was developed by virtue of the general-purpose FEM software ABAQUS.The failure envelopes in different loading spaces were generated.Then,the empirical calculation formulas were given according to the failure envelopes.Based on the relationship between the actual combined loading and the computed failure envelopes,the active state of bucket foundation could be evaluated,and it would be helpful in engineering practices.