The utility model relates to an improved plastic extruded large-area wood imitating flat board structure, which is characterized in that when the bottom surface in a longitudinal direction of the wood imitating flat board is extruded and shaped, the bottom surface is simultaneously provided with T-shaped grooves in a continuous interval shape to correspondingly form reversal T-shaped rib boards in the continuous interval shape on side edges of the grooves one by one. Thus, the consumption of adhesive glue materials of the coating arrangement of the adhesive glue provided by board surfaces of ladder rib boards can be greatly saved by the empty skipping coating arrangement of groove parts. A passage for gas volatilized in the solidifying process of the adhesive glue to outward escape is provided by the arrangement of the grooves to eliminate the phenomenon of residual gas bubbles on the bottom surfaces of board bodies. Parts for absorbing the hot expanding and cold shrinking deformation of the board bodies are simultaneously arranged to enable the board bodies to be smoothly paved and avoid concave and convex deformation after long-period use.