Abstract: The effects of stratification on variation of cold frontal circulation and formation of severe mesoscale convection in the frontal zone are studied by using the primitive equation model,the results show that the variation of stratification has very important in fluences on the frontal circulation,with the decreasing of the static stability the cross-frontal ageostrophic circulation and upward motion are enhanced rapidly,and the posibility in producing mesoscale severe convection and multiple rainbands ahead of the front is also increased,and it is advantageous to excite symmetric instability in frontal zone, however,the effects of stratification on cold-frontal circulation and formation of meso scale severe convective system are mainly determined by stratified states in the lower atmosphere.