Abstract: Using the convention observed data,the NCEP1°×1° grid point material, the mesoscale numerical model WRF,the severe convection in low-latitude plateau on February 28,2008 has been diagnotistic analysed and numerical simulated. The result shows that the severe convection, which occurred under the Spring low temperature, freezing calamity and potential stability condition,cause include strong vertical wind shear, wet low level,adequate vapor served and severe lift movement. In this extremely convection process,severe convection result in the rapid release of strong absolute baroclinic instability,which happen about the wet lingua of low level.The negative twenty degree celsius layer over hailstorm,thunderstorm snow region on 450hPa level,the temperature gradient between zero and negative twenty degree celsius of hailstorm is bigger than the thunderstorm snow’s,the saturated vapor location of hailstorm is higher.Vertical dry potential vorticity (PV)takes on the characteristic of the upper troposphere high PV of strong dry and cold northwest air tends downwards to the low-level and low-latitude,which join with the worm,wet southwest jet on middle and low-level.The WRF simulation scheme in the test has good simulated capability,the case that strong vertical wind shear can cause sever convection under potential stability condition are well validated, the simulation results by WRF meso-scale numerical model such as horizontal wind,lifted condensation level and max convective available potential energy can well indicate the occurrence and kind of strong convection in Yunnan.