Oriented strand board (OSB)

The invention discloses an oriented strand board (OSB). The OSB comprises an OSB substrate layer, a finishing coat and a fine-grain layer, wherein the fine-grain layer is located between the OSB substrate layer and the finishing coat, a basic unit for forming the fine-grain layer is OSB fines with the grain size of 20 to 200 meshes, and the OSB substrate layer is prepared from laminated wood wastes or rotary-cut plate wastes through laminating. The fine-grain layer is additionally arranged, so that the smoothness of the surface of the OSB is improved greatly; and waterproof treatment on the fine-grain layer can be very easily achieved under the condition that the formaldehyde release volume does not exceed standard.