A numerical control horizontal type three-axis drilling and milling tapping machine comprises a machine base, a workbench, a workpiece clamping device, a drilling, milling and tapping device and a control cabinet, wherein the workbench is fixed on a machine frame; the workpiece clamping device is arranged on the workbench in the mode of moving in the X-axis and Z-axis directions of the workbench; the drilling, milling and tapping device comprises a fixed base fixed to the workbench; the fixed base is provided with a milling mechanism, a tapping mechanism and a multi-axis drilling mechanism in sequence at intervals in the X-axis direction; the milling mechanism, the tapping mechanism and the multi-axis drilling mechanism can automatically carry out feeding and retracting along the Z axis of the workbench; the workpiece clamping mechanism, the milling mechanism, the tapping mechanism and the multi-axis drilling mechanism are connected with the control cabinet. So long as rotation of all the machining mechanisms is not affected, the radial direction between the machining mechanisms can be reduced to the minimum. Meanwhile, the workpiece clamping device moves only in the radial direction and the movement distance in the radial direction is greatly reduced, the machining time is saved, and the workpiece machining efficiency is improved.