For understanding the influences of solar radiation to convection of northeaster n cold vortex, a case of severe storm in a cold vortex over northeastern on 12 July 2002 over Liaoning Province was simulated by MM5. The contrasting examinat ions of solar radiation affecting severe storm showed that atmospheric solar rad iation can trigger severe convection by inspiring mesoscale circulation but not by accumulating instable energy in the background of synopticscale system of c old vortex. It is an important condition to trigger this severe convection in co ld vortex that surface shortwave radiation heats up lower layer of troposphere a tmosphere, and produces strong mesoscale convergence and convective instable l ayer onset and maintenance of convection.