In order to improve the surface wettability of wheat straw and increase its bonding strength with adhesives,an aqueous alkali was used to modify the surface characteristics. Based on the theory of spreading penetration,the surface wettability of wheat straw following alkali-treatment was evaluated. The mechanical properties and thickness swelling of the particleboard made from the treated wheat straw were tested and compared with the control wheat straw particleboard. The results showed that both modulus of elasticity and modulus of rupture of the particleboard made with the treated wheat straw were slightly decreased. However,the internal bond strength and 2-hour thickness swell were improved considerably. All properties tested in this study met the product specification of National Standard GB/T 4897-2003 for particleboard.