By using T639 model, conventional observation data and NCEP reanalysis data (1°×1°), the model ability in predicting heavy rain events, together with the governing weather systems, over the Yangtze River Basin in 2008, is validated in the paper. The results showed that T639 model has made a correct prediction for the precipitation area, location and moving trends, the threat score of 24 h rainfall forecast is 56. The primary affecting systems such as the plateau trough, lowlevel southwest jet, southwest vortex and Eurasia largescale circulation background in the high latitudes have obtained a more accurate portrayal. In the test field of various physical quantities, reflecting the heavy rain power structure, the model had a good prediction for the specific humidity and water vapor flux, but a bit weaker for the vorticity, divergence field and wind speed. The work will be helpful in better utilizing the model results in conventional weather prediction, as well as in providing valuable suggestions to further improvement of the model.