The utility model discloses a wood-plastic bed board and an extrusion die thereof. The wood-plastic bed board comprises a board body, concave-convex grains are arranged on the upper surface of the board body, and a concave angle is disposed at one end of the lower side of the board body. A chamfer is arranged at a diagonal line end of the concave angle. The concave-convex grains are direct line grains or arc line grains. The concave-convex grains are arranged on the upper surface of the bed board so that a good stereoscopic effect is achieved, and functions of increasing friction force and skid resistance are achieved. The extrusion die of the wood-plastic bed board comprises a die body and a spure spreader which is located in the die body, the die body comprises a connecting member, a split-flow template, a supporting template, a compression template, a forming template and a mouth template which are sequentially connected, the spure spreader is connected with the supporting template through a plurality of connecting ribs, the connecting member is connected with an extruder head, a die cavity of the connecting member forms a fishtail-shaped flow channel, a flow stopper is mounted in the middle of the fishtail-shaped flow channel, and the flow stopper is fixed with the connecting member through a connecting strip. Material discharging of the extrusion die is uniform and the extrusion die is applicable to the wood-plastic bed board and manufacturing of bed boards made of plastics and the like.