The invention provides a subgrade seepage and drainage blind ditch. The subgrade seepage and drainage blind ditch comprises a base, a frame body detachably mounted on the base and configured as a semi-circular, and a corrugated tube arranged between the base and the frame body, wherein a plurality of water seepage holes are uniformly formed in the frame body; an arc-shaped groove is formed in thearea of the middle of the upper end surface of the base, the lower part of the outer wall of the corrugated tube is closely installed in the arc-shaped groove, the upper part of the outer wall of thecorrugated tube is in close contact with the inner wall of the frame body, a through hole is formed in the trough position where the corrugated tube in close contact with the frame body, and the groundwater in a subgrade can penetrate into the corrugated tube and be discharged from the subgrade through seepage holes and the through hole