Abstract: Cyanuric chloride(2,4,6-trichloro-1,3,5-triazine, TCT)was used as a modifier to modify straw under alkaline conditions, and the structure of straw before and after modification was characterized by IR and ¹³C NMR spectra. The hydrolysis performance of modified straw was test by dilute acid hydrolysis, and the influence of modifier dosage on the hydrolysis efficiency of modified straw was discussed. Test results showed that the yield of the reducing sugar of unmodified straw was only 29.9%, while the highest yield of reducing sugar of the modified straw could be more than 45.5%, as the loading amount of TCT was 9.6%. The analysis result verified that the yield of reducing sugar in acidic hydrolysis of straw could be improved by the appropriate modifications.