Due to the change of carbon sequestration capacity and internal structure and function of forest ecosystems under global warming, it is imperative to assess and predict the response of forest ecosystems to climate change. Based on tree-ring samples collected from Northwestern Yunnan, some tree-ring width chronologies were developed. The main limiting factors of radial growth and the temporal stability of the tree growth response to climate change were analyzed by correlation analysis, spatial correlation, and spectral analysis. The results showed that (1) Temperature was the main factor limiting the radial growth of Larix potaninii in Northwestern Yunnan, and seasonal high and low temperatures alternately affected the radial growth of the Larix potaninii. (2) The relative humidity was closely positively related to the radial growth of Larix potaninii in Northwestern Yunnan. (3) The results of spectral analysis showed that the radial growth of Larix potaninii in Northwestern Yunnan periodically changed and was significantly affected by ENSO and other external forcing. (4) Under the background of climate warming, the growth of Larix potaninii in Northwestern Yunnan presented a decline trend. It provides a scientific decision basis for us to strengthen the protection of natural forest and construct green ecological barrier in Northwestern Yunnan.