The invention provides a workpiece clamping table used for a numerical control milling machine, and a fixing structure thereof. The clamping table comprises a T groove worktable, T sliding blocks and a bearing; the middle portions of the inner end faces of the left side and the right side, relative to the opening end, of each T sliding groove in the T groove worktable are each provided with one rectangular through hole, and the rectangular through holes penetrate through the front end face and the back end face of the T groove worktable. When a rectangular spring in a T groove sealing device is in the common stretching state, rectangular blocks, in two corresponding rectangular through holes, of the T groove sealing device are in left and right end face attaching state, the rectangular blocks jointly seal the opening end portions of the T sliding grooves, in the workpiece cutting process, generated cuttings are sheltered through the rectangular blocks in the T groove sealing device, and cannot fall in the T sliding grooves, the cuttings gathered on the rectangular blocks can be cleaned directly through cleaning manners of a brush and the like subsequently, and the phenomenon that due to the fact that the cuttings block the T sliding grooves, cleaning is difficult can be avoided.