The invention discloses a wooden composite door preparation method, wherein Fraxinus mandshurica Rupr, a walnut wood-plastic composite sheet material, Ormosia henryi, a cherrywood wood-plastic composite sheet material and oak are sequentially subjected to glue coating stacking pressing, and the obtained material is coated with an inner layer coating material and an outer layer coating material toprepare the wooden composite door. According to the present invention, the prepared wooden composite door does not contain formaldehyde; and compared with the conventional composite door, the preparedwooden composite door of the present invention has the following characteristics that the tensile strength is increased by 50-70%, the flexural strength is increased by 40-50%, the flexural modulus is increased by 45-55%, the bearing force is increased by 40-60%, the high-low temperature notched impact strength is increased by 50-60%, the oxygen index is increased by 40-50%, the heat distortion temperature is increased by 25-35%, the two-way anti-warping ability is high, the sound absorption effect is good, the sound insulation performance is good, the heat absorption effect is good, the overall mass is reduced by 15-25%, the toughness is good, the mechanical property is good, the bending stress is high, the internal stress is low, the insect control effect is good, the bidirectional drydeformation is low, the elongation at break is increased by 5-25%, insect pests are avoided, and the product further has advantages of corrosion resistance, moisture resistance, high hardness and goodcold resistance.