According to characteristics of wheat straw board, the making of fire retardant wheat straw boards with four types of fire retardants were investigated by using the orthogonal experiment method. The fire retardant properties of the boards were evaluated by the oxygen index and smoking density. Meanwhile, properties of the boards were tested and analysed. Results showed that the fire retardant properties of the boards have been improved obviously through fire retardants treatment, but some physical and mechanical properties of board decreased. In addition, the optimum technical parameters on making fire retardant wheat straw board were presented.