In the rapidly changing Urban Agglomeration on the Northern Slope of the Tianshan Mountains (UANSTM), urbanization and oasis ecosystem degradation have intensified the need for ecological security planning. However, traditional ecosystem service assessments often struggle to capture the spatial heterogeneity of these fragile landscapes. This study integrates revised ecosystem service value (RESV), ecological sensitivity, and circuit-theory-based connectivity analysis to identify ecological sources and construct an ecological security pattern (ESP). Results indicate: From 2000 to 2020, land conversion among exposed areas, irrigated farmland, and grassland dominated regional change, with 5902 km2 of exposed land converting to grassland and 4554 km2 to irrigated farmland. RESV declined initially but rose overall from 1104 to 1255 billion yuan, yielding a net increase of about 14%. Ecologically sensitive areas were concentrated in the northeast, covering roughly 19,300 km2 and dominated by irrigated farmland. In total, 23 ecological sources, 47 ecological corridors, 28 ecological barrier points, and 61 ecological bottleneck points were identified, forming the basis for a targeted point-line-area protection strategy to guide ecological zoning and restoration. This study provides scientific basis for ecological conservation and territorial spatial planning in arid urban clusters. Nonetheless, limitations related to data resolution and indicator selection remain. Future research should incorporate higher-resolution ecological data and scenario-based simulations to further refine ESP construction.