The invention relates to a manufacturing method of a wedge joint board. The wedge joint board is formed by lengthwise and widthwise splicing of wedge joint slices; the wedge joint slices are cuboid eucalyptus slices with equal width and equal thickness through machining improvement treatment; the short-edge end surfaces of the wedge joint slices are provided with finger-shaped teeth with the same tooth shapes; meshed teeth are jointed to form long wedge joint strips; the long wedge joint strips are jointed by glue in parallel to form the wedge joint board. The manufacturing method comprises the following steps: A, log sawing; B, drying; C, machining improvement treatment; D, width fixing, length fixing and sorting of base materials; E, teeth combing; F, lengthwise and widthwise splicing; G, plate blank repairing, polishing and edge cutting; H, inspecting, packaging and warehousing. The manufacturing method solves the problem that fast-growing eucalyptus is easy to be shrunk and deformed when drying better; through the machining improvement treatment, the machining performance of eucalyptus is greatly improved, the polishing cost, material wastage and glue using amount are reduced, and the production cost is lowered; the manufacturing method has greater promotional value, and contains tremendous economic and social benefits.