Concrete-filled double skin steel tubes (CFDST) have widely been used in constructing high-rise buildings, arch bridges and factories. Much research has been done to study its behaviour under axial compression. However, limited information can be found on its performance under lateral impact loading, especially under blast loading. In this paper, numerical models are developed for CFDST with two different cross sections: one is with CHS (circular hollow section) outer and CHS (circular hollow section) inner, and the other one is with SHS (square hollow section) outer and SHS (square hollow section) inner. Conventional concrete is filled in double skin steel tubes. Different blast loadings are applied on the surface of these columns for dynamic analysis. In addition, different axial loads are also applied on the columns to simulate the combined load condition. The displacement-time history obtained from each simulation is recorded and then compared. The key factors that determine the performance of CFDST columns under blast loading are discussed.