Abstract: Based on the monthly temperature departure data of the underlying surface during the E1 Nino year (1927), a sensitivity simulation of anomalous SST in the Pacific and also in several key areas of the Pacific has been made by using the improved OSU global climatic model. As a thermodynamic forced source, the anomalous SST is put into the model initially as well as the spatial and temporal varieties of anomalous SST with integrated time are superimposed continuously. The results of numerical simulation indicate that the spatial and temporal anomalies for the observed SST in the Pacific, especially in key areas during the E1 Nino year bring about an anomalous change of monsoon circulation in East Asia, and the drought circulation pattern appears. For this change of monsoon circulation, the affecting factors of anomalous SST in both the central equatorial Pacific area and the eastern equatorial pacific area are all very sensitive, so they have a contain significance for weather forecast.