By analyzing the variable characteristics of SST in the Indian Ocean during different phases of ENSO cycle,it is found that the correlation of the variation of SST between in the Indian Ocean and in eastern equatorial Pacific is significant,and the variation of SST in the Indian Ocean is an important component of ENSO cycle.The SST pattern in the Indian Ocean is warm in the western part and cold in the eastern part when SST in the eastern equatorial Pacific is warm,and v.v.Furthmore,the results showed that the most significant area of difference of SSTA between in the Western and Eastern Indian Ocean is in 0～25°S.It's interannual and seasonal change is significant.The zonal difference of SST variation in the Indian Ocean during summer monsoon season is more significant than that during winter monsoon season,and the difference during cold phases is larger than that during warm phases.The correlation coefficient is 0.55 between Dipole Mode Index in the Indian Ocean and SSTA in the eastern equatorial Pacific.