Abstract: Based on tmulti-source observation data and ERA5 reanalysis data, the extreme continuous heavy precipitation process in Ganzi section of Sichuan-Tibet Railway from 20:00 on June 22, 2024 to 20:00 on June 28, 2024 was diagnosed and analyzed. The main conclusions are as follows: (1) During the continuous heavy precipitation, the subtropical high was anomalously westward and stronger, the high ridge in Xinjiang, The southward airflow on the west side of the subtropical high at 500 hPa and the northerly airflow ahead of the high pressure ridge formed a stable shear convergence along the Sichuan-Tibet Railway. At the same time, 200 hPa was the divergence area on the right side of the westerly jet and the diversion area on the northeast side of the South Asian high. The configuration of “low-level convergence and high-level divergence” was conducive to the development of vertical upward movement, which was conducive to the generation and persistence of precipitation. (2) An S-shaped water vapor transport channel developed between the Bay of Bengal and the periphery of the subtropical high, which transported abundant water vapor for continuous precipitation. The total water vapor content reached abnormally high levels with notable extremity. The convergence of water vapor flux in the lower layer increased from afternoon to night, which had a good correspondence with the occurrence time of heavy precipitation. (3) The diurnal variation of CAPE value and temperature had a significant influence on convection activity. The CAPE value increased from afternoon to evening, the convergence field was closely related to the development of convective cloud system, The precipitation cloud system was a mixed echo of stratiform cloud and convective cloud, and its combined reflectivity factor reached 55 dBZ, and the development height of 50 dBz echo exceeded 10 km and 30 dBz was close to 15 km. The convective cloud cluster developed along the shear convergence of600 hPa and 500 hPa, and the enhancement or weakening of Vow parameters would predict the development and weakening of convection, which had certain indicative significance.