Abstract: Based on reanalysis data, multiple sets of satellite retrieval data and the WRF model simulation data, a gravity wave process on 10 January 2005 is identified over the Tibetan Plateau. The impact of the gravity wave on snowfall over the western Tibetan Plateau is also studied. It is found that the gravity wave was located to the left of jet stream exit, and covered most part of the Plateau from southwest to northeast. The wave-like temperature advection pattern and the strengthening of unbalanced flow provided environmental condition favorable for the development of gravity wave. Wavelet cross spectrum analysis shows that vertical vorticity and horizontal divergence in the middle troposphere were consistent with the polarization state of gravity waves. Snowfall was detected over the updraft region in the western Tibetan Plateau, which can be well simulated by WRF. Simulation can also reproduce the mesoscale gravity wave that can hardly be identified in reanalysis data. Numerical simulation shows that the strong diabatic heating near the surface resulted in static instability. Convections were thus easily triggered over the warmer region, which led to latent heat release by condensation over high altitudes. The melting-induced cooling near the ground associated with convection forced the gravity wave development. The formation of solid hydrometers took place over updraft regions, and the subsequent arrival of cold air provided favorable condition for water vapor transport. Weak large-scale ascending motion later replaced the strong updrafts that entered the snow region intermittently. Solid hydrometers then fell onto the ground and precipitation eventually occurred over the western Tibetan Plateau.