The invention discloses a process for manufacturing large-breadth plates by using an all-bamboo modified material, which comprises the following steps of: (1), fully clearing way a surface wax layer and an inner hard layer; (2), modifying and laminating bamboo sheets into sheet bamboo materials which are in strips, filaments and fibres and are cracked but not fragile; (3), degreasing, dying and drying the bamboo material; (4), impregnating, ageing and drying the bamboo material; and (5), rearranging and laying the bamboo material to form blanks, and performing hot pressing on the blanks to mold the blanks into the large-breadth plates of the all-bamboo modified material. The large-breadth plates of the all-bamboo modified material are fine and smooth in vein and compact in structure and are applied to the application field of manufacturing all-bamboo furniture, floors, decoration materials and engineering, construction and military materials, and can effectively and greatly save raw materials, energy, labour cost, production field and storage field. At the same time, because the bamboo material is modified, 10 kinds of bamboos can be selected as processing raw materials.