It was observed that the cationic silicone-acrylic latexes produced possessed remarkable chemical stability. The surface sizing agent containing this type of cationic silicone-acrylic latex, even in the absence of aluminum salt, was excellent in improving the water resistance and mechanical properties of the corrugated paper. Compared with that of the pure anionic cassava starch sizing agent, the Cobb value of the sizing agent that consisted of 99.6% anionic cassava starch and 0.4% cationic silicone-acrylic latex, in which the dosage of vinyltriisopropoxysilane was 4%, decreased by 40%, and the ring crush index increased by 20%.