Abstract: The mesoporous molecular sieve solid acid catalyst MCM-41—SO3H was prepared by grafting—SH on MCM-41 molecular sieve，then oxidation and acidification were made.The catalyst was also characterized.The reaction on cyclodehydrtion of xylose into furfural using MCM-41—SO3H has been studied.When the mass ratio of xylose to catalyst was 0.8，the reaction temperature was 170 ℃，and the reaction time was 4 h，the conversion of xylose was 83.4%，the selectivity of furfural was 76.7%，and the furfural yield was 64.0%.The advantages of the catalyst were that the furfural yield was higher than using sulfuric acid as catalyst，and no acid waste water generation and the catalyst can be used repeatedly by regeneration treatments， but the furfural yield decreased to 39.7% when regenerated catalyst was used.

Key words: mesoporous molecular sieve；MCM-41&mdash, SO3H；solid acid；dehydration；furfural