Abstract:In order to explore the possible formation mechanism and flow pattern of extreme precipitation caused by the echo training of typhoon rainbands, we researched the circulation situation and the convection organization of there echo training processes after the landfall of the typhoon Soudelor (No.1513, process 1)，the typhoon Fitow (No.1323, process 2) and the typhoon Matsa (No.0509, process 3) by using multiple observation data and the ERA5 reanalysis data. The results show that the rainstorms of the three processes all occurred on the windward slope of the hills at the eastern part of Zhejiang province, directions of the rain belts were consistent with the background air flows, and convergence of water vapor flux were mainly concentrated below 850 hPa. In process 1, the rain belt happend between the low pressure and the subtropical high, the vertical wind shear and the CAPE are large, and the water vapor comes from tropical ocean surface and the wet layer is thick. Process 2 takes place in a saddle-shaped field between the residual vortex of a typhoon over land and another typhoon over the sea, and the vertical wind shear and CAPE were weak, water vapor comes from the sea surface at mid-latitude, and the wet layer is located in the middle and lower level of the troposphere. Process 3 is caused by the spiral rain band in core region of typhoon, the vertical wind shear is strong and the CAPE is the minimum. The structure and organization of the rain belts in the three process are obviously different. In Process 1, the boundary layer convergence and the convective system are the most highly developed, the baroclinic structure of the mesoscale convergence line promotes the uplift of warm and humid air from the sea surface, and the convergence field strengthenned the degree of organization. In Process 2, the wind direction of the weak cold pool is opposite to the easterly airflow, while with similar wind speed and shallow convergence, the new cells continue to form at the eastern boundary of the rain belt, and disappear at the western boundary, the stagnation of rain belt caused continuous belt-like heavy rainfall area. In Process 3, the spiral bands were affected by the typhoon vortex dynamics, the rain belts developed lowly, and the structure tilts slightly to the outside, and the rain belt developed with the wind speed convergence caused by the fluctuating of southeast jet, which resulted in the echo training with the largest hourly rainfall intensity among the three processes. The above facts show that the echo training of typhoon rainbands that causes extreme precipitation is formed in various ways, and the short-term forecast faces challenges.