The development of straw particleboard is the direction and key point of wood reduction and substitution in packaging industry. Wheat straw was pretreated with coupling agent and alkali composite treatment to modify its adhesive properties. Straw particle board was prepared with the pretreated straw and wood shavings. The effects of different factors on straw pretreatment and the ratio of straw/ shavings on properties of straw particle board were studied. The results showed that the optimized pretreat condition is the usage of KH-550 3%, modification time 90 min, and temperature 60 ℃; elasticity modulus, static bending strength, and oxygen index decrease, while the expansion rate of water absorbing of the straw particle board increase, with the increase of straw/ shavings ratio. It was concluded that composite treatment of coupling agent and alkali has more obvious improvement than single treatment; increase of straw usage amount will cause the performance fall down of straw particle board.