Abstract: To optimize the use of agricultural water resources and improve the efficiency of agricultural production, it is essential to quantitatively assess long-term trends in crop water use efficiency (CWUE). In this study, three typical crops (cotton, maize, and winter wheat) were studied in the oasis agricultural area of the Manas River Basin located in the northern slope of the Tianshan Mountains of Xinjiang. Long-term agricultural meteorological observation data from 1980 to 2023 at the Wulanwusu Agrometeorological Station in the basin were used, and correlation, trend, and geographic detector methods were applied. This study was to clarify the long-term trends of CWUE for three typical crops and to analyze the contribution of meteorological factors and management measures to CWUE. The results of this study showed that over the past 44 years, the yields of the three typical crops in the basin showed an increasing trend, their evapotranspiration showed an increasing trend first and then a decreasing trend, and their CWUEs changed from slow changes at the beginning to rapid improvement. The CWUE of the cotton and maize showed the greatest increasing trends in the stage of drip irrigation with film mulch (LD), with the annual growth rates at 0.0221 and 0.2812 kg·m⁻³·a⁻¹, respectively, and the CWUE of winter wheat showed the greatest increasing trend in the stage of drip irrigation without film mulch (ND), with the annual growth rate at 0.0943 kg·m⁻³·a⁻¹. Among all the factors affecting CWUE, the effect of management measures on CWUE was greater than that of meteorological factors, and their contributions to the CWUE of cotton, maize, and winter wheat were 63.02%, 61.75%, and 58.86%, respectively. Among the management measures, irrigation methods had significant effects on CWUE for the three crops; varieties showed the largest effects, while only the effect on maize was signifincant. Among the meteorological factors, the CWUE of cotton was mainly affected by the accumulated temperature which ≥ 0 ℃, the CWUE of maize was mainly affected by the sunshine hour, while these effects on the CWUE of winter wheat were not significant. This study provides essential scientific data to support the efficient management and utilization of agricultural water resources in the northern slope of the Tianshan Mountains of Xinjiang, thereby ensuring food security and promoting sustainable agricultural development in the region.