<p>The temporal and spatial patterns, environmental effects, and evolution mechanisms of precipitation stable isotopes in the source region of Yellow River were analyzed in this study. The main results are as follows: The δD-δ¹⁸O relationship has been established and formulated as δD = 7.49δ¹⁸O + 8.28 (R² = 0.95), indicating a strong correlation. Notably, the annual average δ¹⁸O displays a trend of increasing first and then decreasing from southwest to northeast. Furthermore, seasonal variations are evident, with higher δ¹⁸O levels observed during summer and autumn compared to winter and spring. The concentration of precipitation stable isotopes is impacted by sub-cloud evaporation, with temperature and relative humidity being the primary driving factors. Notably, the spatial pattern of d-excess during the summer half-year mirrors the trend of evaporation rates, both of which decrease as the season progresses. However, as altitude increases, the evaporation rate gradually intensifies. The enrichment rate of δ¹⁸O in precipitation shows a decreasing trend in temporal terms and a decreasing trend from west to east in spatial terms. As the precipitation event progresses, δ¹⁸O decreases continuously and is negative under the influence of leaching. The source of water vapor in the study area is basically stable, and the main source of water vapor is westerly water vapor. The complex path of water vapor transport and local factors jointly determine the characteristics of stable isotopes in precipitation in the source region of the Yellow River. Hence, future endeavors in research should primarily concentrate on delving into the impact of sub-cloud evaporation and the circulation of moisture recycling on the precipitation stable isotopes.</p>