Objective To improve the interfacial compatibility of lignocellulose with thermoplastic plastics, and increase the mechanical properties of wood-plastic composites. Methods The contact angles of three probe liquids against unmodified and modified corn stover fibers were tested by capillary rise method, and the surface tension and its components of unmodified and modified corn stover fibers were calculated based on the method of Owens-wendt-Kaelble. Results The results showed that the surface tension of the unmodified corn stover fibers was 28. 88 mN/m and its polar component was 22. 20 mN/m, while the surface tension of the modified corn stover fibers was 35. 69 mN/m and its polar component was 3. 51 mN/m. Conclusion Modified corn stover fibers had better interfacial compatibility with thermoplastics, which was also confirmed by the better mechanical properties of wood-plastic composites.