Abstract: Plywood is the wood product which is made of multi-veneer through adhesive bonding, and it has been widely applied in architecture, furniture, and packaging. Improving the processing quality and productivity of the veneer is a very important issue in plywood production. Due to the inevitable presence of defects such as knots, cracks, and holes in the veneers produced by wood rotary cutting machines, a digging-filling repair by using the veneer digging-filling machine tool is required. Currently, the veneer patching in China generally relies on manual, and the working process includes picking defects and punching. Among them, common defects of veneers include joints, holes, cracks, decay, discoloration, skin clips, etc., which have irregular distribution and inconsistent shape and size.Because the selection and placement process of defects is completely dependent on the subjective judgment of the operator, the lack of clear repair standards and efficient process flow, so the repair effect is often difficult to ensure. From the two aspects of veneer defect detection and repair mechanism and machine tool, the research status of automatic veneer defect repair technology and digital twin technology of veneer repair machine at home and abroad is summarized, the existing problems are summarized and the future development trend is pointed out.