Abstract: To investigate the patterns of snow change in the Third Pole region, this study examines the temporal and spatial characteristics of snow depth on the Qinghai-Tibet Plateau over the past 40 years. Additionally, it conducts a partial correlation analysis to assess the relationship between snow depth and near-surface temperature, as well as average precipitation. The analysis utilizes long-term datasets of daily snow depth in China (1979—2021) and the China meteorological forcing dataset (1979—2018). The results of the spatiotemporal variation analysis reveal a decreasing trend in snow depth across the Qinghai-Tibet Plateau, particularly in its three interior regions. This trend is more pronounced on a monthly scale, particularly during autumn and winter. However, the eastern part of the plateau experiences a significant increase in snow depth. The partial correlation analysis demonstrates a strong negative correlation between snow depth and temperature across all scales, with a maximum negative partial correlation coefficient of approximately −0.8. On the other hand, snow depth and precipitation exhibit similar spatial distribution but have distinct correlation patterns on an annual and monthly basis. Overall, the correlation between snow depth and precipitation follows a “positive in east and negative in west” distribution pattern during spring and summer, while autumn exhibits a more widespread positive correlation, with most areas showing a positive correlation above 0.4. On a daily scale, temperature exhibits the strongest negative partial correlation (−0.733) with snow depth, with a 10-day delay, while precipitation demonstrates the highest positive correlation (0.064) with snow depth, with a 3-day delay. The variation characteristics of snow depth and its correlation with meteorological factors on the Qinghai-Tibet Plateau exhibit significant spatiotemporal heterogeneity. This heterogeneity can be attributed to factors such as topography, ablation and accumulation time, and the influence of monsoons and westerlies around the plateau.