Over the last two decades, the repeated Interferometric Synthetic Aperture Radar (InSAR) has proven to be useful for accurate topographic mapping and ground-surface motion monitoring. However, atmospheric delay variations are one of main errors in SAR interferograms. Since the GPS stations are sparse and the water vapor product of multispectral sensors is sensitive to the presence of clouds in the Tibetan Plateau (TP), the water vapor delay distribution maps are estimated by integrating GPS Radio occultation (RO) observations and National Centers for Environmental Prediction (NCEP) data, which are used to mitigate the atmospheric phase delays in SAR interferograms. Results shows that GPS RO inferred wet delay together with NCEP model can generate more detailed wet delay distribution map