Study Region: The "Dong-Kang-Ejin" urban agglomeration in the middle of the Yellow River basin in China. Study Focus: Arid stormwater assessments often equate runoff with usable water and lack systematic evaluation. This study proposes five evaluation indicators covering the entire process of urban stormwater resource utilization and establishes a land-use-based assessment framework for stormwater resources. Using the SWMM model, the runoff processes of 152 rainfall events from 2009 to 2020 were simulated for three cities. The stormwater resource and its economic benefits across four distinct use categories were evaluated at different temporal and spatial scales. This achieves a full-process quantitative assessment of stormwater resources in arid regions, encompassing "rainfall-runoff-collection-treatment-utilization. New Hydrological Insights for the Region: Results show significant spatiotemporal heterogeneity in arid-region stormwater use. Runoff collection rates are Kangbashi (61%-64%) >= Dongsheng (60%-63%) > Ejin Horo Banner (56%-59%). Rainfall utilization (4%-10%) is below the typical urban benchmark (15%-20%). The annual utilizable runoff rate for the entire area is 3.77:1.83:1 across wet-normal-dry years. Utilizable runoff under design rainfall (p = 5a to 100a) ranges from 2.30 to 4.87 million m & sup3; . Differentiated allocation of treated rainwater to agricultural, industrial, domestic, and ecological uses yields potential economic benefits of 94.18 (wet year), 54.51 (normal year), and 26.62 (dry year) million yuan.