<p>Vegetation change is the most intuitive and sensitive bioindicator reflecting seasonal and interannual variations in the external environment, and it can directly reflect the rapid response of terrestrial ecosystems to climate change. Using remote sensing and meteorological data, this study revealed the spatiotemporal characteristics of leaf area index (LAI) in the north of China during 1982–2022, clarified the response of LAI change to different meteorological factors, quantified the impacts of climate change and human activities on LAI change, and predicted the future trends in LAI change. From 1982 to 2022, the vegetation in the north of China generally showed a greening trend with a change rate of 0.0071 m²/(m²•a). Temperature was strongly positively correlated with LAI and was the main climate factor driving LAI change. Residual analysis revealed that vegetation improvement occurred in across 74.53% of the study area, and vegetation improvement in about 96.83% of the improved zone was attributed to a combination of climate change and human activities. The regions where anthropogenic contribution exceeded 60.00% covered 36.83% of human-affected areas, while the regions where climatic contribution exceeded 60.00% covered 19.77% of climate-affected areas, demonstrating that human activities influenced the intensity of LAI change more deeply despite the broad spatial impact of climate change. Human activities such as afforestation and the Three-North Protective Forest Program played the dominant role in vegetation greening compared to climate change. Hurst index analysis indicated that 80.30% of vegetation in the north of China is expected to experience a non-sustained improvement in the future. These findings will provide a scientific basis for optimizing the protection strategies of the national ecological barrier areas and evaluating the effectiveness of major ecological projects.</p>