The invention discloses a dampproof and anti-cracking PVC wood plastic door plank and a preparation method thereof, and relates to the technical field of novel energy-saving door plank production. Thewood plastic door plank is prepared from the following raw materials of PVC resin powder, enveloped calcium silicon powder, chlorcosane, ardealite, aerated aluminum powder, aluminum silicate fiber, lignocellulose, a calcium-zinc stabilizer, a foaming agent, a foam stabilizer, a dry strength agent, a plasticizer and a coupling agent. The preparation method of the PVC wood plastic door plank comprises the steps of uniform mixing of the raw materials, extrusion, modeling, cutting, engraving, deburring, transfer printing, stoving varnish, solidifying, inspecting and the like. The PVC wood plasticdoor plank is simple in preparation technology and low in raw material cost, has the properties of environmental protection, watertightness and moisture resistance, corrosion crack resistance and high strength and toughness, and is long in service life and wide in application range.