Analysis is made of the May-September averaged circulationof the model atmosphere(referred to as the background circulation inthis paper)from the general circulation model(GCM)developed by theInstitute of Atmospheric Physics(IAP), Academia Sinica. Results showthat during an E1 Nino episode, a variety of important systems(SouthernOscillation. the Walker and Hadley circulations, the western Pacificsubtropical high and ITCZ)and extensive rainfall all undergo consider-able anomalies and the abnormalities occur mainly in the NH westernPacific tropical and subtropical latitudes.Analyses presented here arein good agreement with those of observational data, thereby demonstrating the prospects of the GCM in the research on low-latitute circulations.