A floating machining workbench device, comprising a base (9) and a workbench (6) capable of floating and moving on the plane of the base (9), the workbench (6) is provided with a horizontal axis drive device (8) and a vertical axis driving device (7), the horizontal axis driving device (8) includes a horizontal axis motor (81) coupled with a horizontal axis screw (82), and the vertical axis driving device (7) includes a A vertical axis motor (71) coupled with a vertical axis screw (72), wherein, the right side of the workbench (6) is provided with a longitudinally extending protrusion (61) so that the longitudinally extending protrusion (61) and A suspension part (680) for lateral driving is formed between the bases (9).