Abstract: The baroclinic instability in nonzonal basic flows is studied by using a twolayer model.The influences of the basic current on the baroclinic instability are discussed.The results show that the appearance of baroclinic instability is more favorable in the nonzonal flows.As is well known,disturbances usually acquire strong development in highlatitude.According to our model,the development of the disturbance is driven by baroclinic instability of the vortex wave (shear wave) in nonzonal basic flows.