The dynamical characteristics were investigated for the development process of Mongolia cyclone related to a severe sand-dust storm event which occurred in East Asian during 5-9 April 2002. The results show that there was obvious baroclinic forcing in the processes of the formation and the development of the cyclone. The vorticity advection at 500 hPa level and the thermal advection and atmospheric heating rate from 1 000 hPa to 500 hPa level were important factors; the main contribution to the intensification of cyclone came from the thermal advection, the action of thermal advection in the lower troposphere was greater than the others when the cyclone reached peak intensity phase; the effect of atmospheric heating rate accounted for dominant status while the cyclone was weakening, but the effect of vorticity advection and thermal advection was secondary; Q vector frontogenesis function further indicated that the function of the atmospheric baroclinicity could not be overlooked. The vertical transport of potential vorticity is significant. In addition, the two maxima of IPV from upper and lower troposphere, respectively, merged to each other when the peak of cyclone intensity appeared. High level jet happened in the origination and development processes of the cyclone all the time, which not only favored the development of the Mongolia cyclone, but also triggered the low level jet; it implied that there is coupling between high level jet and low level jet in troposphere during the developing process of the cyclone.