Abstract: It is one of the key fundamental issues in design and construction of bucket-foundation-supported offshore platforms to evaluate overall stability behavior and failure mechanisms of structures and foundations under combined loading. However, as a new type of foundation, the bearing capacity and practical performance of suction bucket foundation under combined loads remain unaddressed. Based on the Swipe test procedure of loading, implementing a three-dimensional finite element method in the framework of the general-purpose FEM software package ABAQUS, this paper proposes the empirical calculation formulas of failure envelopes of bucket foundation in different loading spaces. The stability of active state of bucket foundation can be estimated based on those equations, which can supply referential resources for design and construction of suction bucket foundation.