Abstract: Utilizing conventional observation data and numerical model data including CMA_3KM, ECMWF and CMA-GFS, a typical sudden localized short-duration heavy rain event that occurred in Yibin on June 20, 2022, was analyzed, and the application and correction of the CMA_3KM model data was also conducted. The results indicate that: (1) The weather event was triggered by a low-level shear line formed by disturbance flows at the base of an upper-level trough, under relatively abundant thermal instability and certain moisture conditions in the southern basin. (2) Due to sufficient reserves of thermal unstable energy, combined with weak shear line intensity, limited impact area, and the failure to establish a low-level jet, the event showed characteristics of suddenness, high intensity, localization and short duration. (3) During the sudden localized short-duration heavy rain event, commonly used numerical models failed to predict the heavy precipitation. Among them, CMA_3KM demonstrated the best performance, with its short-term forecast data closely matching the actual intensity and timing of the heavy rainfall, providing valuable guidance for forecasting and early warning operations. (4) Combining ECMWF low-level wind field data with CMA_3KM precipitation forecast data effectively improved the correction of the heavy precipitation area.