[Objective]The historical change of dune activity index of Ongniud Banner in Horqin sandy land in Inner Mongolia was studied,aiming to provide guidance to control desertification in this area.[Methods] The climatic factors influencing dune activity and desertification were analyzed,and the dune activity index was calculated based on historical meteorological records from 1957 to 2014.[Results]The climatic condition had a clear changing trend which was more obvious since the year of 1998 with reducing precipitation, increasing temperature,and declining surface wind speed.The dune activity index after 1998 was 34%less than that before 1997 with seasonal changes of-28%,-32%and-38%during spring,autumn and winter. The summer index increased 7%after 1997 but had limited influence on the yearly trend due to its low absolute average value of 13.[Conclusion]The changes in dune activity index indicated a more appropriate climate for fixing sand dunes and reversing desertification,however,sand dunes could still be fully activated under the current nature environment.The drier and warmer climate will further intensify the water shortage problem.Artificial desertification control measures need to be proposed to improve the natural environment in the Horqin sandy land.