Abstract: A two-dimensions hailcloud model,that is a slabsymmetrical,the dynamic equations include all the factors as completd as possible,the micropysical procedure of cloud-precipitation has been improved and might describe the biparameter veriable evolution of size-distribution of hyparameter veriables,has desingned.A new lateral boundary scheme has suggested which may be refered suspending boundary and an operative technique of outline of hydrometeor feild has developed.By use of this scheme and technique we have successfully simulated the structure of weak eche region (WER) and studied the patterns of airflow in the cases of differant wind shear and differant intensity of heat disturbance.The results indicate that:1.The formation of boundary WER,unboundary WER and the double WER were simulated successfully;2.The pattern of convective airflow is various,which pattern can be occoured was dependent on the interaction among the shear intensity of environmental wind,stratification and heat disturbauce condition.