The horizontal beam up and down mobile CNC gantry milling machine is a mechanical processing equipment that integrates advanced technologies such as machinery, electronics, and hydraulics. It is suitable for semi precision and precision machining in industries such as aviation, heavy machinery, locomotives, shipbuilding, power generation, machine tools, automobiles, printing, and molds, and can also be used for rough machining. The overall structure of the gantry boring and milling machine consists of a gantry frame, which is composed of double columns, movable crossbeams, connecting beams, transverse slides, and milling head slide pillows to form a rigid frame. The crossbeam moves up and down along the column guide rail (W-axis), and a vertical high-power multifunctional slide pillow type boring and milling head is configured on the crossbeam. The boring and milling head slide board moves left and right along the crossbeam guide rail (Y-axis) and up and down (Z-axis), and the worktable moves longitudinally along the bed (X-axis).