The Mount Altai region marks the southern boundary of the West Siberian Taiga Forest, increasingly affected by global change. However, the pivotal factors influencing the growth stability of the Taiga Forest amidst climate change remain unclear. This study utilizes remote sensing data on Leaf Area Index (LAI) and the LAI Gini coefficient, a stability characteristic index, to assess growth stability changes in the Altai Mountain Taiga Forest from 1982 to 2018. A multivariate linear model is employed to analyze the impacts of climatic conditions, vegetation productivity, vegetation height, and vegetation types. Findings reveal that: (1) There was a significant interannual increasing trend in thermal conditions, characterized by Potential Evapotranspiration (PET), over the past 38 years, with low stability; conversely, interannual variation in water conditions, characterized by Saturated Water Vapor Pressure Deficit (VPD), exhibits minor trends, with PET primarily influencing Taiga Forest growth stability. (2) Growth stability in the Taiga Forest is lower at higher altitudes and higher at lower altitudes, primarily influenced by vegetation productivity indicated by average LAI. For dense forests (Mean LAI > 2.091), the higher productivity correlates with lower stability, whereas for sparse forests (Mean LAI ≤ 2.091), the higher productivity correlates with higher stability. Additionally, the biological factors' influence surpasses that of climatic factors. Amidst climate change, Taiga Forest growth in high-altitude areas with lower stability may decline, while Taiga Forest with higher productivity assumes more ecosystem functions, exacerbating threats due to decreased stability. As a crucial ecological security barrier, future Altai Mountain Taiga Forest protection should prioritize areas with high altitude and productivity to mitigate climate change's impact on regional ecological security.