In this work, a numerical method using a direct coupling algorithm is proposed for electromagneto-thermo-mechanical (EMTM) coupling analysis of structures in strong magnetic and thermal field. Both the electromagneto-mechanical (EMM) coupling effect and thermal effect are considered in the structural dynamical analysis. To realize this algorithm, a direct coupling element including degrees of freedom of displacement, temperature and electromagnetic fields is developed on the platform of the ANSYS user programmable features and verified by the comparison between the experimental data and simulation results of a typical EMTM problem. Finally, the EMTM dynamic response of a simplified model of the HL-2M vacuum vessel during plasma vertical disruption events is simulated. According to the simulation results, the EMTM coupling effect is found significant and necessary to be considered for the design and safety evaluation of Tokamak structures.