[Objective] The spatiotemporal variation characteristics and driving mechanisms of net ecosystem productivity（NEP） were investigated in order to provide a scientific basis for the refined evaluation of regional carbon budgets and the optimization of ecological and environmental management strategies. [Methods] Xuzhou City, a resource-exhausted city in Jiangsu Province, was selected as the study area. By integrating MOD17 A3 remote sensing products with meteorological observation data, and applying Theil-Sen median regression analysis, coefficient of variation, Hurst index, and optimal parameters-based geodetector methods, the spatiotemporal evolution patterns, fluctuation characteristics, future trends, and driving factors of vegetation NEP in Xuzhou from 2001 to 2023 were quantitatively analyzed. [Results] ① The multi-year mean NEP in Xuzhou was 141.36 g/（m²·a）(calculated as C), showing a statistically significant upward trend with an annual increase of 1.690 g/（m²·a）. Spatially, NEP exhibited a clear gradient pattern, with higher values in the northwest and southeast and lower values in the central region, forming a pronounced southeastward-increasing distribution.② From 2001 to 2023, NEP increased in 67.70% of the study area, while 13.49% experienced a decline. Highvolatility regions covered a much larger area than low-volatility regions, indicating relatively low NEP stability during the city's transition.③ Hurst exponent analysis（mean value: 0.425） indicated a tendency for future NEP trends to reverse compared with those observed over the past 23 years.④ Optimal parameters-based geodetector results identified the main driving factors of NEP variation in Xuzhou, ranked by explanatory power, as vegetation cover, environmental pollution, soil and water conservation capacity, socioeconomic development, and human activity intensity. Climate factors（temperature and precipitation） and landscape patterns played secondary roles. [Conclusion] Although Xuzhou has gradually enhanced its carbon sink capacity during the transition period, its overall stability remains limited, and there is a potential risk of future functional reversal. To maintain and strengthen regional carbon sink capacity, it is necessary to optimize vegetation restoration pathways, improve pollution control, and achieve a balanced integration of socioeconomic development and ecological protection.