Net primary productivity (NPP) of terrestrial ecosystems served as a key indicator of vegetation carbon sequestration capacity. The Shaanxi section of the Qinling Mountains as a vital ecological barrier in Shaanxi Province and its surrounding areas, investigating the spatiotemporal patterns of NPP and their driving mechanisms was crucial for understanding regional carbon cycling. This study utilized Google Earth Engine (GEE) to derive NPP data (2001—2023) for the Shaanxi section of the Qinling Mountains and analyzed its spatiotemporal patterns. The Theil-Sen median trend analysis along with the Mann-Kendall significance test revealed the trend features of NPP changes in the Shaanxi section of the Qinling Mountains from 2001 to 2023. By integrating the optimal parameters-based geodetector (OPGD) and partial least squares structural equation modeling (PLS-SEM), we quantified the impacts of multiple drivers on NPP spatiotemporal divergence patterns. The results showed that during the study period, the mean annual NPP in the Shaanxi section of the Qinling Mountains was 602.20 g C m-2 a-1, and the spatial distribution pattern was characterised by a high in the north-west versus a low in the south-east, and the rate of change of the interannual variation was 5.57 g C m-2 a-1 (P<0.01), of which 81.62% of the area exhibits a highly significant increasing trend, 11.48% of the area shows a significant increase trend and the area of insignificant change is mainly located in the southeastern part of the study area as well as in the gully areas. The primary factors influencing the spatial pattern of NPP are evapotranspiration, precipitation, and the kernel normalized difference vegetation index, with a total explanatory power of over 0.67. The strongest influence on NPP is the interaction between evapotranspiration and precipitation, following by the interaction between evapotranspiration and temperature, which had an explanatory power of 0.502 and 0.460, respectively. Climate, topography, and human activities directly affected NPP and indirectly influenced NPP through vegetation indices (e.g., altitude → human footprint → evapotranspiration → kernel normalized difference vegetation index → NPP). This research revealed the mechanisms and impact pathways of multiple driving forces coupling on the temporal and spatial NPP divergence patterns within the mountain ecosystems of the Shaanxi section of the Qinling Mountains. This study provided a scientific basis for the ecological protection and management of the Shaanxi section of the Qinling Mountains and offered valuable insights for understanding the complex mechanisms driving spatial and temporal divergence patterns of NPP in other mountainous terrestrial ecosystems.