Abstract: With conditions of approximately actual beckground wind field in typhoons and a barotropic nondivergent model in a cylindlical coodinate,the Problem of instability of the Perturbation in tyPhoons is discussed. The resultS show that the warm core structure of typhoons and the activity of Properly strong cold air in the periphery are advantageous to the Perturbation development in typhoons,and the stronger the typhoons,i. e. the lowet the pressure,the easier the perturbation in typhoons would develop.