The stable isotopes of hydrogen and oxygen in precipitation over the Qinghai-Xizang Plateau and their related proxy data such as ice cores and tree rings are of great significance for a deeper understanding of the cli‐ mate and hydrological changes on the Qinghai-Xizang Plateau. The introduction of stable water hydrogen and oxygen isotope modules in atmospheric circulation models helps understand the climatic interpretations of precipitation isotopes and related paleoclimate proxy data. In recent years，some studies have applied nudging techniques to these models to reduce model errors by fusing reanalysis data. However，further research is needed to deter‐ mine the extent to which this method improves the simulated precipitation isotopes. This study used data from the Qinghai-Xizang（Tibetan）Plateau Network Isotope Plan（TNIP）to evaluate four atmospheric models with water isotope modules and compare the results with and without nudging reanalysis data. The results indicate that all four models can well reproduce the climate mean annual precipitation δ18O and seasonal variability of precipitation δ18O，while the models have lower simulation ability for interannual variability of precipitation δ18O. The simulations of the spatial distribution and seasonal cycle changes of precipitation δ18O over the Qinghai-Xizang Plateau with nudging reanalysis data is significantly better than that of free running simulations. The differences in model choice have a greater impact on the simulation results than the differences in nudged reanalysis data. Overall，the fusion of reanalysis data can effectively correct the model bias in the atmospheric circulation over and around the Qinghai-Xizang Plateau，thereby improving the model's ability to simulate precipitation and precipitation δ18O. This study provides a useful reference for simulating stable isotopes of precipitation over the Qinghai-Xizang Plateau using models and the improvement effect of nudging techniques on the hydrological and climatic simulation of the Qinghai-Xizang Plateau.