Abstract: Many authors have shown that in China, the contribution due to surface friction to the height tendency of an isobaric surface is of the same order of magnitude as those of the large-scale topographic influences and that under some special weather situations, the non-adiabatic heating is non-negligible to the height tendency even if in short-range forecasting. By taking into consideration of above mentioned three effects, a two-parameter baroclinic model suitable for numerical weather prediction is derived from the combination of hydrodynamic and thermodynamic equations. The solutions of the system of prognostic equations are given:Then this paper deals with the truncation errors in the numerical weather prediction when a triangular grid-point system is used.. Moreover, an optimum smoothing formulas for the field is developed. Finally, the author gives a brief discussion on the problem concerning the development of the large-scale baroclinic disturbances.