Abstract: This study aims to clarify the spatial evolution and influencing factors of the cropland and reservoirs in the Economic Belt on the North Slope of Tianshan Mountains (EBTM), particularly for food security and high-quality agriculture in arid areas. The kernel density analysis, center of gravity model, and spatial dislocation index were used to explore the spatial relationship and evolution between cropland and reservoirs in EBTM from 1980 to 2023. The location entropy and geographic detector were used to reveal the dominant factors of spatial imbalance. The results show that: 1) The area of cultivated land in EBTM shared an expansion trend from 1980 to 2023, increasing from 2.25 to 3.37 million hectares, an increase of 50.1%. At the same time, the number of reservoirs in EBTM continued to increase, from 112 to 269, an increase of 140.2%. The reservoir capacity in EBTM shares an increasing trend, growing from 4.0×10⁹ m³ to 1.0×10¹⁰ m³, with a growth rate of 155.0%. As such, the cropland area and reservoir capacity showed an expanding trend. The high-density areas were consistent in space, but the high-value area of the reservoir was significantly smaller than that of cropland. 2) There was a spatial dislocation between the cropland area and the reservoir capacity, but the overall dislocation was smaller. There was a positive correlation on the spatial mismatch between cropland and reservoir capacity in EBTM, accounting for 58.5%. The expansion of the arable land was greater than the replenishment rate of reservoir capacity. 3) There were different spatial preferences for the geographical distribution of the cropland and reservoirs. But they all tended to be close to rivers, with the small slopes and low urbanization rate. The spatial distribution of the cropland was preferred the plains and plateaus with the low altitude, flat slope, near rivers, low urbanization level, and high degree of agricultural mechanization; The spatial distribution of the reservoirs was preferred the plateaus or small/medium undulating mountains with the medium to high altitudes, flat slopes, near rivers, and low levels of urbanization. 4) The spatial distribution of cropland and reservoirs was dominated by the complex factors, among which the total power of agricultural machinery, the output value of the primary industry and the distance from the river dominated the spatial distribution of cropland, and the distance from the river. The altitude and topography dominated the spatial distribution of the reservoir. The factor interaction indicated that the explanation of the inter-factor interaction for the spatial analysis of cultivated land and reservoirs was greater than that of the single factor, indicating the nonlinear and dual factor enhancement. There was the spatial matching of the cropland and reservoirs in EBTM. The finding can provide the scientific support for the decision-making on the "land determined by water " strategy, as well as the optimization and regulation of water—land resources in arid areas.