The use of Hierarchical Systems (HS) method in design and control of a robotic system for welding (RSW) is suggested in the paper. Created conceptual model of the robotic system under consideration integrates connected systemic descriptions of the RSW mechatronic subsystems -IT, electronic, mechanic -which are given in the common HS theoretical basis. RSW structure and the motion planning task, RSW dynamic presentation in its environment, RSW control unit, and RSW learning by demonstration processes are also given in this basis. The examples of the RSW control processes, robot teaching and welding process simulation using Mimicking Kit and RobWork program system respectively are also described in the work.