Abstract:NCEP reanalysis data (horizontal resolution of 1°×1°, vertical level 26 layers) and a variety of conventional observation data and real time typhoon positioning data from Central Meteorological Observatory are used to analyze the features of No.1330 typhoon Haiyan. The weather analysis and dynamic diagnostic methods are used to explore “Haiyan” dynamic mechanism of strengthing development and fast moving, and to excavate forecast key points to raise the capability of Central Meteorological Observatory in forecasting similar typhoons in the future. The main conclusions of this paper are: (1) “Haiyan” continues to strengthen and keeps strength before landing Philippines in the simultaneously strengthening of the subtropical westerly jet in the course southward and the easterly wind located in the south side of subtropical high. (2) The strengthening of subtropical westerly jet in the course southward is an important cause for the strengthening of the subtropical high and the easterly wind in the south side of the subtropical high in all tropospheric layers. (3) The distribution of “Haiyan” horizontal wind speed is obviously asymmetric, showing the easterly is greater than the westerly, the southerly is greater than the northerly, and the characteristics of the zonal wind asymmetry is more pronounced. The enhancement of shear positive vorticity caused by the asymmetry of the zonal wind and meridional wind may be the important cause for the intense development of “Haiyan” before its landing Phillppine. (4) The enhancement of horizontal convergence in the lower troposphere and the existence of vertical meridional circulation may be another important cause. (5) The main dynamic mechanism of the continuously strengthening of Typhoon Haiyan is horizontal convergence in lower troposphere and tropospheric vorticity increase significantly in inner core and the enhancement of divergence in upper troposphere and the decrease of wind shear in its environmental area. (6) For typhoon in autumn and winter, in addition to the western Pacific subtropical high, westerly trough, the lower troposphere easterly winds, cross equatorial flow, it is important to pay attention to the changes in the upper troposphere subtropical westerly jet stream, especially to the westward typhoon. The strengthening of the subtropical westerly jet may cause typhoon movement to accelerate significantly and intensify. Furthermore upper troposphere not only impacts the change of high level outflow of typhoon, but also plays some guiding roles in typhoon movement as well as the upper circulations.