The invention relates to a graining roll-coating production-line method for carpentry waterborne coating material on medium density fiber board. The invention is characterized by the following steps: (1) processing raw material; (2) roll coating waterborne white primer; (3) roll coating middle-coating primer; (4) roll printing to color; (5) roll coating fining varnish. The invention is advantageous in that the environment-friendly waterborne carpentry material and the novel coating method are applied on low-priced heavy density fiberboards to produce high-quality furniture boards with graining coating effect, provided with low coating consumption, high coating effectiveness and low coating cost]