The analysis of works on rational design of steel combined trusses is carried out. It is noted that the problem of finding a system of minimum weight of steel combined trusses with a rational distribution of internal forces has been most fully studied so far. It is shown that rational design does not always provide the smallest value of the chosen criterion. The actual task of choosing the main parameters (regulation of the internal stress-strain state) of the combined truss is considered, the solution of which allows to identify the optimal design solution with a minimum weight, cost of material or minimum cost (cost “in fact”).The problem of truss optimization is formulated as a deterministic problem of nonlinear programming. The design variables are the cross-sectional dimensions of the truss rods and geometric parameters, providing the considered methods of calculated regulation of the stress-strain state of trusses. Describes software for formulating and solving optimization problems of relevant structures. The program provides the formation of virtually arbitrary truss topology from a set of available node types. The finite element method is used for static calculation and determination of design state variables. To solve the parametric optimization problem, the program provides for the use of the capabilities of the software complexes LIRA-CAD, MONOMACH, ANSYS, ROBOT, etc.