Eucalyptus chips were used as raw materials for manufacture of fire proof and water resistant wood based composite board. Effects of chip treatment on properties of the board were examined. The results indicated that chip treatment influenced the physical and mechanical properties of the board greatly. Chips treatment suitable for manufacture of fire proof and water resistant wood based composite board could be adopted as follows: 1)chips were submerged in 0.2% NaOH for 48 hours under room temperature; 2)chips were submerged in 10%～15% sodium silicate for 48 hours under room temperature.