The optimization of the construction solutions for building structures is obviously reasonable because in case of making optimal solutions the cost of construction and further operation can be essentially cut. Relatively small changes in construction solutions may lead to essential changes on the stage of construction and operation. According to the traditional approach a designer usually develops a limited number of variants, consideration of which doesn’t guarantee the closeness of the final result to optimum. That means, the problem of the development of new and optimization of the existing optimization methods for design solutions remains current. The article is devoted to the current problems of choosing the optimal design solution for steel structures of industrial buildings. The authors offered an algorithm for computer-aided design and obtained a design solution on the example of a truss implemented in PC ANSYS. As optimization variables the truss height, steel grade and element section type are considered. The algorithm allows determining the value of the minimum truss weight for trusses of various classes and types of section. Also the corresponding optimum truss height is estimated, which gives a minimum design weight for different types of sections.