Effects of reaction time, temperature and acid concentration of acid hydrolysis from Carya cathayensis Sarg. shell to xylose were investigated. The dynamics model of the acid hydrolysis was established. The model was verified by experiment. The optimum extraction parameters were: temperature was 363.15K, concentration of hydrochloric acid was 1.2mol/L and acid hydrolysis time was 5h. The apparent activation energy of the transformation to xylose was 70.91kJ/mol. The relationship between the reaction rate constant, temperature and acid concentration was as follows:lnk1=21.4540－8.5290/T－5.0632lnC. 