Abstract: The Xinjiang modern oasis is an example of a long-term expansion of the oasis arable land in regiments of the Xinjiang Production and Construction Corps and local townships under different operating modes (corps farm and local household contracting). This paper used image data from six periods (1958 to 2018) to assess the change degrees of land use of the 144 Regiment of Shihezi Reclamation Area and Lanzhouwan Town of Manas County in the Manas River Basin. This study examined the process of oases expansion in regiments and local town, and analyzed the driving forces of expansion using multiple stepwise regression. Finally, to assess oasis expansion in the whole basin, the oasis expansion model was used to calculate the appropriate scale of oasis cultivated land. The oasis change process in the 144 Regiment and Lanzhouwan Town had obviously increased the arable land area, and the increased arable land was mainly transformed from grassland and forest land. The driving factors of the regiment arable land expansion were water-saving irrigation area, water resources runoff, and average income of farming and herding industries. The local driving factors were income per capita, average income of farming and herding industries, and gross agricultural product. Moreover, the arable land in the basin had greatly exceeded the appropriate size, and the potential ecological security had been highlighted. All levels of government in the basin should follow the concept and construction requirements of "mountains-rivers-forests-farmlands-lakes-grasslands life community" to promote the comprehensive development of the basin, accelerate the construction of a modern land resource management system, scientifically delineate the ecological red line, strictly limit the scale of oasis expansion, and promote optimal land use by the corps and localities. Adherence to the strictest water resources management system, "water to determine the land" could aid efficient water resource use, prevent and control oasis desertification, promote soil degradation management and land remediation, and improve the efficiency of land use to protect the quantity, quality, and ecology of the oasis arable land.