The Expert System (ES) was developed at the Ural Federal University for the analysis and design of bar rolling technologies and it can be used in the optimization of existing and design of new processes of bar rolling. For the operation of the ES a knowledge base was created about the subject area, based on theoretical and experimental studies, as well as generalizations of experience in the production of rolled bars at existing mills. A comprehensive mathematical model of calculation of rolling passes and technological rolling, created on the basis of modern ideas about the mechanics of deformable bodies, allows the calculation of a full range of technological and energy-power parameters of the simulated process. The ES software was developed for operational system Windows using the visual programming environment of Borland C++ Builder.