[Objective]Clarifying net primary productivity (NPP) changes and driving factors is of great significance to measure the carbon sequestration capacity of vegetation and support carbon sink trading. [Objective]We obtained net primary productivity date based on MODIS-NPP data, and combining the Theil-Sen Median trend analysis, Mann-Kendall test, and revealed the net primary productivity characteristics of spatiotemporal variation in Kunming from 2001 to 2020. We also adopted the optimal parameters-based geographical detectors (OPGD) model to explore the fluence mechanisms of climate, topography and anthropogenic factors on NPP. [Results] (1) The annual mean distribution of vegetation NPP in the Kunming City was spatially and temporally heterogeneous, with a distribution pattern with higher in the west and lower in the east, and increased significantly at an average annual growth rate of 7.08 g.c.m-2/a. (2) The increased fragmentation of the vegetation landscape had a significant negative effect on the vegetation NPP, which was mismatched with the annual mean of vegetation NPP; and the change of vegetation NPP was a result of the increase in the fragmentation of the landscape and a significant negative effect on the spatial and temporal distribution of vegetation NPP. (3) Changes in vegetation NPP are the result of the combined effects of climatic, anthropogenic and topographic factors, in which the kernel Normalized Difference Vegetation Index (kNDVI), land surface temperature, and vegetation landscape fragmentation have stronger explanatory power than the factors of temperature, precipitation, and slope, and the interaction between the factors better explains the spatial and temporal changes in vegetation NPP. The study provides methodological ideas for research on the carbon sink capacity of vegetation and terrestrial ecosystems in similar regions.[Conclusion]Over the past two decades, the Net Primary Productivity (NPP) of vegetation in Kunming has generally shown an increasing trend. However, the ecological situation in certain areas of the main urban district remains concerning. Moving forward, comprehensive planning should be implemented to scientifically promote the coordinated development of ecological protection and socio-economic growth, ensuring both sustainable environmental improvement and the balanced progress of urbanization.