Abstract: A equatorial B-plane barotropic model is used to discuss the influence of the diabatic factors such as heating of condensation, evaporation-wind feedback and CISK on the Kelvin and Rossby waves. We have obtained the angular frequency and analyzed the period of waves and stability. It is shown that the existence of the diabatic factors enlarges not only the period of adiabatic waves changes but also the stability of waves. And we think that the so-called low-frequency oscillations are a kind of diabatic waves which are important factors producing the short-term climatic changes.