The invention belongs to the technical field of aluminum alloy, and relates to a machining technology of an ultrawide 6061 aluminum alloy panel for a military test detection platform. Aluminum alloy is prepared from, by weight percentage, 0.63-0.69% of Si, 0.45-0.55% of Fe, 0.2-0.3% of Cu, 0.08-0.12% of Mn, 1.05-1.15% of Mg, 0-0.1% of Zn, 0.013-0.02% of Ti, 0-0.05% of Zr, 0-0.05% of single impurities, and the balance Al, wherein the total weight percentage of the above raw materials except Al is smaller than or equal to 0.15%. The lost pass is added in the hot rolling process, during shallow pass, by cooling the panel with rolling mill air-blowing equipment, the purpose of uniformly and slowly lowering the finish rolling temperature is achieved, arching of the back of the panel due to theexcessive width is avoided, and the problems that for the ultrawide 6061 aluminum alloy panel prepared through an existing machining technology, the contradiction between the width and flatness of thepanel and the machining deformation is prominent, and it is hard to meet customer needs are solved.