To study the causes for rapid weakening and dissipation of Typhoon Bavi(2008) after its landfall in the north , a numerical simulation was carried out using the non-hydrostatic mesoscal model WRF(Weather Research Forecast) , and the simulated results were verified by the observation data. Furthermore, based on the high-resolution simulation results, the weather circulation background and the characteristics of environmental field change were analyzed before and after the landfall of Bavi. The results indicate that the simulated track, intensity change and precipitation distribution of Bavi all matched with the observations well before and its landfall. Bavi was guided by the southwestly airflow in front of the mid-latitude westerly trough, and was located on the right side of the upper-level jet entrance area before its landfall, the divergence field at upper levels was conducive to maintaining the typhoon circulation. After Bavi made landfall, on the one hand, the reduction of the upper-level jet on the north side of typhoon and the weakening of the upper-level divergence inhibited the development of typhoon convection; on the other hand, the sinking strong cold air invaded into the center of typhoon from the northeast side of the low level, which destroyed the vertical warm-core structure of Bavi, then the height was reduced and inclined to the east. In addition, the strong vertical wind shear, especially from middle to up levels, was unfavorable for typhoon sustention, and the lack of water vapor supply is another reason for the rapid weakening and disappearance of the typhoon after its landfall.