Abstract: Reclamation of abandoned cropland can increase effective cropland supply and strengthen agricultural production capacity, but whether reclaimed abandoned cropland is compatible with regional water resource conditions and can remain under stable cultivation has not been adequately evaluated at the national scale. Based on the Annual China Land Cover Dataset from 1990 to 2023, this study reconstructed cropland-use trajectories at a 1 km × 1 km grid scale, identified abandoned cropland reclaimed during 1997–2015, and traced its post-reclamation utilization trajectories through 2023. According to subsequent land-use trajectories, reclaimed abandoned cropland was classified into four types: stable reclamation, re-abandonment, multiple abandonment–reclamation cycles, and withdrawal from agricultural production. Crop yield data, cropping structure, multiple cropping index, the standardized precipitation evapotranspiration index (SPEI), and the crop water scarcity index (CWSI) were integrated to evaluate agricultural production contribution, water resource supply–demand mismatch, and utilization stability. SPEI was used to characterize growing-season climatic moisture conditions, whereas CWSI was used to quantify the mismatch between crop irrigation water demand and available blue water resources under the existing cropping structure. The results showed that abandoned cropland reclaimed during 1997–2015 accounted for 5.41% of the historical cropland extent, defined as the spatial union of all areas identified as cropland at least once during 1990–2023, and 65.16% of the reclaimed abandoned cropland remained continuously under cultivation from reclamation through 2023. In 2016, reclaimed abandoned cropland under cultivation accounted for 5.08% of the national cropland area and contributed 5.57% of national crop production, indicating a slightly higher crop output per unit area than the national cropland average. After 2016, the share of national crop production contributed by reclaimed abandoned cropland under cultivation declined to 4.33% by 2023, mainly because some reclaimed areas were re-abandoned or withdrawn from agricultural production. Reclaimed abandoned cropland under cultivation and stable cropland showed no significant difference in growing-season SPEI (p = 0.937), indicating that the two types of cropland were located under similar climatic moisture conditions. In contrast, reclaimed abandoned cropland under cultivation had a significantly higher CWSI than stable cropland (p < 0.001), indicating a stronger mismatch between crop water demand and available blue water resources. This difference became more pronounced in drought years, suggesting that reclaimed abandoned cropland was more vulnerable to water resource pressure when climatic water stress intensified. The median CWSI of grid cells dominated by stable reclamation was 5.17, significantly lower than those of grids dominated by re-abandonment, multiple abandonment–reclamation cycles, and withdrawal from agricultural production, with corresponding median values of 9.99, 10.50, and 15.16, respectively. Meanwhile, the other three post-reclamation trajectory types generally had lower yields than the stable reclamation type. Spatial coupling analysis further showed that high-production-contribution and high-CWSI zones were mainly concentrated in northwestern China and the western part of northeastern China, where reclaimed abandoned cropland contributed to agricultural production but also faced strong water resource constraints. In high-CWSI regions, grids with a low proportion of stable reclamation accounted for the largest share, reaching 41.54%. These findings indicate that water resource supply–demand mismatch is an important constraint on the stable utilization of reclaimed abandoned cropland. Therefore, reclamation suitability assessment should not rely only on land availability or production potential, but should incorporate water resource suitability and post-reclamation stability. Reclamation planning should further promote water-adapted reclamation, optimize crop structure, improve irrigation efficiency, and implement differentiated regional regulation to support the long-term stable use of reclaimed abandoned cropland.