In recent years, the study on hydrological effect of land use change has become a focus. In the Tarim River Basin, land use change has exerted great effect on hydrological process of a river, so it is necessary to study the hydrological effect of land use change in the river basin. As cultivated land dominates the land use type in the Tarim River Basin, based on the statistical data of cultivated land of each prefecture and tested data of each main water station in Tarim River Basin, this paper analyzes the total variation trend, variation speed, regional difference and hydrological effect on water quantity of the river. The results are shown as follows. (1) The cultivated land area in the Tarim River Basin shows a fluctuating increasing trend with an annual rate of 2.37%, but per capita cultivated land area saw a gradual decrease with an annual rate of 0.44%. There is a significant spatial disparity in the cultivated land changes. The change of cultivated land area in Bayingolin Mongol Autonomous Prefecture where the reserved land and water resources are plentiful is large, and that in Hotan Prefecture located at the northern foot of Kunlun Mountains is small. (2) As a result of the expansion of cultivated land area in the Tarim River Basin, the hydrological effect such as river process, river discharge, flood, water quality and silt are more remarkable than before, and the spatial effect on river discharge is striking. As a result of cultivated land expansion, cultivated land and consuming water rise by 34.80% and 21.78% from 1957 to 2006, respectively. At the same time, water pollution and the decreasing of the water quality have become the confinement of social development in the Tarim River Basin. At present, the project of water saving has taken effect, and the trend of the venting water quantity from streams to the Tarim River has been under control. In order to keep the sustainable development in this region, it is urgent to harness the Tarim River in a long term, set up coherent management system of water resources, and use water resources reasonably.