This dissertation is focused on research of Thermally modified oak wood machining process. It is an analysis of factors that influence the energy indicators - cutting wattage. We try to observe in this research an impact of the independent factors (wood thermal modification, vc- cutting speed, vf- pulling speed, angle geometry of tool and type of tool) influencing energy difficulty by flat milling process of the thermally modified (T= 160 °C, T = 180 °C, T = 200 °C, T = 220 °C)wood and its comparison with native wood. We reached resulting findings by this experimental measuring those were statistically analysed and evalueted.The experiment goal is to find and evaluate parameters that mostly influence the energy difficulty by flat milling process. Our measurements results to a facts of an inspected factors influence to cutting wattage in this order: cutting speed, angle geometry, Thermal wood modification, pulling speed, type- toolset.