Abstract: First, the differences between the propagating path and amplitude distribution of quasi-stationary planetary waves forced by a forcing source over middle latitudes and those forced by a forcing source over low latitudes in a winter basic current are theoretically discussed. It is pointed out that the anomaly of heat source over low latitudes may largely influence the anomalies in the tropo- spheric circulations over middle and high latitudes, while the anomaly of heat source over middle latitudes may play an important role for the stratospheric circulation anomalies. A quasi-geostrophic, 34-level spherical coordinate model with Rayleigh friction, Newtonian cooling and horizontal eddy thermal diffusivity is used to compute the disturbance patterns responding to an anomaly of heat source over middle latitudes and over low latitudes, respectivily. The computed results show that the anomaly of heat source over low latitudes may largely influence on the winter circulation anomalies over middle and high latitudes, and the anomaly of heat source over the tropical Pacific Ocean may cause the PNA (the Pacific/North America) pattern anomalies.