This paper is concerned with the geometrical similarity of heat conduction-elastioplastic structural problems. When the dimensions of a structure are geometrically scaled down/up, the similarity relations for both isolated heat conduction and elastoplastic structural problems are derived. For cases of thermo-structural coupled, it is concluded that heat conduction-static elastoplastic problems can be geometrically similarly scaled down/up and a set of similarity relations are drawn accordingly. As examples, a full-, half- and quarter-scale unilaterally-tensioned plate and internally-pressured cylindrical shell irradiated by a laser pulse are numerically analysed and the numerical results have confirmed this conclusion. However, heat conduction-dynamic elastoplastic problems are found not to comply compatibly with the geometrically similar scaling.