A hidden drainage structure for a door frame or window frame sash at least comprises a lower frame bar mainly made from an alloy resin section bar. At least the outdoor side wall of the alloy resin section bar is connected with a layer of aluminum alloy section bar, a water outlet notch is formed in a middle cavity of the alloy resin section bar from top to bottom, and the lower end of the aluminum alloy section bar is provided with a downward water outlet communicated with the water outlet notch. The aluminum alloy section bar is clamped to the outdoor side wall of the alloy resin section bar through an upper clamping mortise and a lower clamping mortise. The inner end edge of the alloy resin section bar is provided with a notch towards indoors, the notch forms an installation groove for hollow glass through a pressing strip located on the indoor side, the two edges of the hollow glass are embedded in the installation groove through installation rubber strips, and the water outlet notch of the alloy resin section bar is located below the outdoor side of the installation groove of the glass. The hidden drainage structure has the advantages that the structure is simple, use is convenient and reliable, water permeating in a door and a window is drained easily, and attractiveness of the door and the window can also be kept.