The Master's thesis deals with the mechanical design of electric machine rotor. Within the first two chapters of the practical part of the thesis two simplified computational models of the rotor (level 1 models) are compiled. Specifically, the model of flexible rotor mounted on rigid supports and model of rigid rotor mounted on flexible supports. The essence of these computational models lies in solvability using simple equations. Using these models can save time when constructing a pre-design of the rotor geometry. The following chapter is devoted to comparing different approaches to computational modeling of rotor using FEM. A predetermined preliminary design of a high-speed massive rotor is investigated. Computational models of different levels at stress-strain analysis and modal analysis are presented. It also includes a suggestion on how to proceed effectively in a given analysis.