The desertification concept was introduced into China in 1977 when the United Nations Conference on Desertification was held Although much research on it has been done since then, the exact status and causes of desertification are still beyond researchers’ understanding Over the past 50 years, the losing rate of land to desertification has been escalating Among the most severe desertified areas is the Ortindag Sandy Land, located in Inner Mongolia plateau and to the north of Beijing, which is a dust and sand source area that threatens Beijing and Tianjin regions It is experiencing severe desertification, whereas there is short of relevant studies on it at present The trend of rapid expansion of desertification was realized through researches on some local areas in this region The desertification status and trends in the whole region of Ortindag Sandy Land, however, are still unclear To date, knowledge about the causes of desertification is no more than a general understanding that irrational human activities such as overgrazing can induce desertification Human production system and land system interlace and interact There is a complex feedback mechanism between them It is vital to reveal the feedback mechanism for the understanding of the causes of desertification and control of desertification Finally, we advocate four key issues and research priorities relevant to desertification of the Ortindag Sandy Land, ie potential ecosystem spatial patterns, desertification trends and monitoring, desertification mechanisms.