A convective adjustment scheme developed for the p-σ combined vertical coordinate five-layer primitive equation model is presented in detail in this paper. Besides the temperature, the humidity field is also adjusted with this scheme. The use of this scheme has made the avoidance of the hydrostatic unstable which occured in the upper layer when the original limited layer dry convective adjustment scheme for T, q and ??? was used, and allowed us to carry the integration of the model over a much longer period. The simulated distributions of the precipitation rate are also improved.