Abstract: In a 2-dimensional axial symmetrical primitive equation model, the effect of cumulus momentum transference is studied. We assume that the convective heating are related to the vorticity and the vertical flux of cumulus mass at a certain level. The simulated typhoon got in this paper is closer to the actual typhoon on the structure than the result obtained with Ekman pumping. Therefore, it is similar to Ekman pumping that the cumulus momentum transport can arouse the conditional instability of the second kind (CISK) which leads to the genesis and development of typhoons. Probably, the cumulus momentum transport is more important to the formation and maintenance of typhoons than the effect of Ekman pumping.