毛乌素沙地位于我国北方农牧交错带，生态环境非常脆弱。基于长时序多源遥感数据，分析了1964—2020年毛乌素沙地新垦耕地与弃耕地的空间格局变化及其对荒漠化的影响。结果显示：（1） 1964—2020年毛乌素沙地新垦耕地和弃耕地面积变化可分为3个阶段。1964—1986年新垦耕地和弃耕地面积均较大，年均弃耕地面积是1986—2020年的2.89倍；1986—2007年新垦耕地和弃耕地面积均较小并且相对稳定；2007—2020年新垦耕地面积增长迅速，年均新垦耕地面积是1964—2007年的3.24倍。（2） 新垦耕地和弃耕地表现出明显的空间分布差异。1964—1986年新垦耕地集中分布于沙地中部和西部，以及南部部分区域；1971—2010年新垦耕地只在沙地南部和东部区域局部出现；2010—2020年沙地南部和东部区域新垦耕地大幅度增加，2015年以来开垦强度有所降低。1964—1971年弃耕地集中分布于沙地东北部以及中部和南部部分区域，1971—1986年弃耕地在沙地南部分布比较集中，同时也散布于沙地东北部以及中部和西部部分区域；1986—2020年弃耕地面积大幅度减少，仅在沙地南缘和东部部分区域出现。（3） 1964—1986年毛乌素沙地的耕地弃耕使弃耕地及其周边区域发生了强烈的荒漠化；2010—2020年新垦耕地周边区域荒漠化土地并未出现扩张现象，但荒漠化程度存在加重趋势。耕地开垦和弃耕主要受政策因素驱动。近年来毛乌素沙地的大规模耕地开垦对其荒漠化的长期影响需要持续关注。

The Mu Us Sandy Land, located in the agro-pastoral ecotone of northern China, has a fragile ecological environment highly susceptible to agricultural development. This study employs long-term multivariate remote sensing data to analyze the spatio-temporal patterns of newly cultivated and abandoned farmland in the region from 1964 to 2020 and their subsequent impacts on desertification. The results indicate that (1) From 1964 to 2020, changes in the area of newly cultivated and abandoned farmland in the Mu Us Sandy Land can be categorized into three stages. Between 1964 and 1986, the extent of both newly cultivated and abandoned farmland was relatively high, with abandoned farmland significantly exceeding other periods. The average annual abandoned farmland area was 2.89 times that of 1986—2020, and newly cultivated farmland in pastoral areas was notably greater than that in agricultural areas. Between 1986 and 2007, both newly cultivated and abandoned farmland remained relatively low and stable, with newly cultivated farmland slightly exceeding abandoned farmland. From 2007 to 2020, the area of newly cultivated farmland expanded rapidly, with an average annual increase 3.24 times that of 1964—2007, while the abandoned farmland area remained relatively low. (2) Significant spatial and temporal differences exist between newly cultivated and abandoned farmland. From 1964 to 1986, newly cultivated farmland hotspots were widely distributed in the pastoral areas of central and western Mu Us Sandy Land. Between 1971 and 1986, a few concentrated cultivation hotspots emerged in the agricultural areas of eastern Mu Us Sandy Land. From 2007 to 2020, newly cultivated farmland hotspots were mainly concentrated in the east, central agricultural areas, and the southern region. (3) Between 1964 and 1986, large-scale farmland cultivation and abandonment, driven by policy factors, led to severe land desertification in the Mu Us Sandy Land. The area of fixed sandy land surrounding abandoned farmland decreased by 99.9%, while the area of shifting sandy land increased by 358.2%. From 2007 to 2020, no significant trend of desertification was observed around newly cultivated farmland; however, the degree of desertification surrounding newly cultivated farmland showed an increasing trend. Future agricultural and animal husbandry management policies, as well as desertification prevention and control plans, should carefully balance agricultural development with the preservation of fragile sandy ecosystems. Additionally, attention should be given to the potential desertification risks associated with land reclamation and abandonment.