Abstract: Abstract: With the rapid development of the economy and population since the adoption of an open and reform policy, cultivated land is continually reduced in China under the multiple impact of occupation for construction and the implementation of an ecological restoration and environmental protection project. Understanding the temporal variation of cultivated land and grasping the spatial distribution trends have become an important research topic. This has an important guiding significance for the study of food security and sustainable development. With the support of a long temporal land use dynamic database, this paper analyzed the change process of cultivated land from the end of 1987 to 2010 in China, revealed the spatial-temporal characteristics of cultivated land changes, and analyzed the main causes in the last 30 years. The national dynamic database has was 6 sets of land use data (1987, 1995, 2000, 2005, 2008 and 2010) and 5 sets of dynamic data (1987-2000, 1995-2000, 2000-2005, 2005-2008, and 2008-2010). Remote sensing images with 20-30m spatial resolution (TM/ETM+, CBERS and HJ-1A), visual interpretation, field surveys, and much auxiliary information were applied during construction of the database. We extracted the cultivated land information from the land use database, and analyzed the spatial-temporal change of cultivated land after data statistics and dynamic transfer matrix calculation. The results show that: In the most recent 30 years, the total area amount of Chinese cultivated land was relatively stable. The original cultivated land kept reducing since the end of the 1980s in the whole nation. On the other hand, the newly reclaimed land distributed mainly in northern China kept increasing. The new reclaimed land partly offset the original cultivated land loss, so that the center of new reclaimed land gravity was gradually moving from northeast to northwest. The moving of new reclaimed land gravity caused the productivity of new reclaimed land to be reduced. The year of 2000 was the turning point of the change process, because the total area of cultivated land was increased slightly from the end of 1987 to 2000, but reduced from 2000 to 2010. Because the speed of cultivated land increase was obviously higher than the reduction, the total area of cultivated land was increased from the end of 1987 to 2010. The spatial pattern of the cultivated land change process showed that cultivated land distributed in north China was increased, but those in south China were decreased. The Yangtze River delta and Pearl River delta were the fastest decreased regions in which cultivated land was distributed, and Xinjiang, Heilongjiang and Inner Mongolia were the fastest increased regions. The situation of land use type change showed that construction land occupation was the main reason that cultivated land decreased, and the trend of occupation is still rising. Ecological construction occupied cultivated land was the main reason in the ecologically vulnerable area. Reclaimation of grassland and forest was the primary source of cultivated land increase. In recent years, more and more unused land was reclaimed to cultivated land, such as saline-alkali land, swampland, and even sandy land and Gobi. Because a series of problems of water resources and the environment will become prominent during the process, unused land reclamation should be carried out particularly carefully.