By using the NCEP／NCAR reanalysis data and the diagnosis analysis method of wavepacket propagation(WPD),the wavepacket propagation and accumulation characteristics of the heavy snowstorm on March 24—25,2005 in Tibet were analyzed.Results show that the characteristics of wavepacket were in better accordance with the snowfall area at 500 hPa.The perturbation energy accumulated and increased obviously during the heavy snowfall process.This process was mainly influenced by the low value system of the Indian Ocean and the Bay of Bengal,which transported sufficient vapor to Linzhi area.The cold air from high latitude area and the southwest airflow interacted with each other,which also promoted the occurrence of this heavy snowstorm process.