Abstract: Aba Prefecture is located at the southeastern margin of Qinghai-Tibet Plateau and the core area of the ecological barrier in the upper reaches of Yangtze River. The spatiotemporal dynamics of vegetation net primary productivity (NPP) in this region have important indicative significance for regional ecological security. Based on remote sensing data from 2001 to 2020, the spatiotemporal variation characteristics and driving mechanisms of vegetation NPP and soil erosion in the study area were systematically analyzed. The results showed that the multi-year average NPP of the study area was 426.37 g C m⁻² a⁻¹, with a spatial pattern of higher in the southeast and lower in the northwest. The overall NPP showed a fluctuating upward trend, with 81.92% of the region experiencing vegetation improvement. The mean coefficient of variation of NPP was 0.080, indicating higher stability than most ecologically fragile areas. The mean Hurst index was 0.676, showing strong overall persistence, suggesting that the vegetation would generally improve in the future but there was a risk of degradation locally. NPP decreased significantly with increasing altitude, with higher values on shady slopes than on sunny slopes, and exhibited a unimodal pattern in response to topographic relief, peaking at the 50−500 m interval. The implementation of ecological projects was the main driving factor for vegetation restoration and soil erosion reduction, while local human activities and extreme climate events still had negative impacts on the ecosystem. This study could provide a scientific basis for ecological protection and restoration in the eastern margin of Qinghai-Tibet Plateau.