The invention provides a new agricultural furrow irrigation dike overflow plate. The new agricultural furrow irrigation dike overflow plate comprises a sinking plate, a side telescopic face, a back telescopic face, a first floating plate, an embedded cabin, a second floating plate, a land ridge ditch, conical thorns, a foam plate, a connecting plate, a covering plate, an upper sinking cavity, a water overflow opening, a rotating shaft and a blocking face. The conical thorns are integrally arranged at the bottom of the sinking plate. A side telescopic surface and a back telescopic surface are correspondingly arranged and are connected through a Z-shaped surface; the widths of the side telescopic surface and the back telescopic surface are sequentially reduced from top to bottom; one side ofthe hollow trapezoid is open; through the arrangement, a cavity is formed between the side telescopic surface and the back telescopic surface; when water is accumulated in the cavity, the buoyancy ofwater flow enables the first floating plate to ascend, then the side telescopic face and the back telescopic face extend to form a trapezoid shape and exactly conform to the cross section of the furrow; and therefore the effect of blocking the water flow irrigated in the furrow is achieved.