Evapotranspiration (ETc), crop water requirement (Dcr), irrigation (IR) and irrigation leaching amount (IRlc) play a critical role in optimizing irrigation scheduling and are also important for hydrological cycle processes and ecological environment in arid regions. This research examined the spatiotemporal variability of the ETc, Dcr and IR of cotton using data from 16 meteorological stations in the Tarim basin (TRB) of arid Northwest China during 1961-2017. The results showed that the mean annual ETc of cotton exhibited a significant decreasing trend, with a change rate of 12.965 mm10 a-1 and 18.357 mm10 a-1 during 1961-2017 and 1961-1990, respectively. Subsequently, it experienced a substantial increase with a change rate of 16.833 mm10 a-1 after 1990. The Dcr of cotton followed a decreasing trend at a rate of 15.531 mm10 a-1 and 21.99 mm10 a-1 during 1961-2017 and 1961-1990, respectively. The Dcr of cotton provided an increasing trend at a rate of 20.164 mm10 a-1 during 1991-2017. The IR of cotton followed a decreasing trend at a rate of 19.66 mm10 a-1 in 1961-2017 and 24.531 mm10 a-1 in 1961-1990, but an increasing trend at a rate of 14.437 mm10 a-1 in 1991-2017. The IRlc of cotton decreased by 2.566 mm10 a-1 and 3.663 mm10 a-1 during 1961-2017 and 1961-1990, respectively. After 1990, it experienced a substantial increase by 3.331 mm10 a-1. Wind speed exerted the greatest influence on the variability in Dcr and IR between 1961 and 1990, while shine hour played a more prominent role in explaining the variability in Dcr and precipitation may have played a more significant role in explaining the variability in IR. This study is helpful for the scientific planning for agriculture, water resource allocation and water-saving irrigation in arid regions.