The analytical calculation technique of high-altitude mast structures, reinforced with cable stretches, was developed in conditions of longitudinal-transverse bending. A numerical algorithm for deformed scheme calculating based on the stepwise loading of the finite element mast model was proposed. Comparative calculations of the masts selected versions with the use of developed software modules and SCAD and ANSYS software complexes are carried out. Parametric optimization problems of constant mast structures and two-step stiffness, with fixed and variable position of stretch marks were formed and solved. On the basis of the developed two-level algorithm, an effective design of a two-stage mast with an optimal arrangement of stretch marks was obtained.