Abstract: The dynamical characteristics of an intense stratospheric sudden warming occurring from December 2003 to February 2004 are diagnosed by using the ECWMF daily data. Due to the higher pressure levels and vertical resolution, the evolution of polar vortex is investigated by analyzing the distribution of isentropic potential vorticity at different levels; the activities of planetary wave are explained by studying the Eliassen-Palm (EP) flux and its divergence, and the variation of meridional circulation and its impact on chemical transport are researched by analyzing the residual mean circulation. The results show that: (1) This stratospheric sudden warming (SSW) event has a long and intense process.(2) The earliest warming broke out in the higher stratosphere, then spread down to lower layer. The upper westerlies and vortex recovered promptly after the generation of easterlies at 10 hPa, while the lower stratosphere continued warming.(3) The planetary wave is so active that it propagated from the troposphere to the stratosphere several times, and the wave number 1 played a major role.(4) The residual circulation in the stratosphere reversed after SSW, inducing the alternation of transmission between high and low latitudes and distribution at different vertical levels. These results will lay the foundation for advanced investigation in the Stratospheric-Tropospheric Exchange (STE) and further development of GCM study.