The invention discloses a wood-bamboo-
straw fiber board, and belongs to the technical field of 
forest product manufacturing. The 
fiber board is made from any one or two sorts of 
fiber materials from wood, bamboo, 
straw, or natural biological 
insect-
resist agents including tobacco stick and the like, 3 to 5 percent of 
preservative, additives such as treating compound, reinforcing agent, waterproof agent and the like, 12 to 40 percent of fiber soakage 
moisture content, 6 percent of reinforcing agent 
starch, 0.5 to 1 percent of waterproof agent 
wax and 
rosin latex and 1 to 3 percent of hard board reinforcing agent; and the density of the mixture is controlled to be between 380KG / m<3> and 1,200 KG / m<3> so as to be made into the fiber board. Meanwhile, a preparation method provided reduces wood consumption, makes comprehensive and efficient use of 
straw and reduces environmental 
pollution caused by fiber board manufacturing through adopting straw burning and a wet method; moreover, the preparation method saves auxiliary materials and energy sources, thereby reducing cost; the wood-bamboo-straw fiber board does not have 
toxicity and public 
hazard, and is capable of being recycled and degradated to form beneficial biological cycle; and the intensity and decorative performance of both fiber board and composite board are improved, thereby enlarging application range.