Levulinic acid (LA) can be prepared from corn stalk with SO42--TiO2/clay solid acid as hydrolysis catalyst. The effects on the amount of solid acid, hydrolysis temperature, hydrolysis time and liquid-solid ratios on the LA yield had been discussed in this thesis. Quadratic regression model was founded and optimization was analyzed by response surface method (RSM). The experimental results showed that the optimal conditions as follow: hydrolysis temperature was 241℃, hydrolysis time was 31min, SO42--TiO2/ clay solid acid was 4.5%, and liquid-solid ratio was 14∶1 (V/W...