Abstract: Based on complete and reliable SSt and SOI data during 1950-1997, according to SS tanomalies in the eastern and central Pacific an index is defined to determine ENSO episodes. An intensity index was produced according to accumulated anomalies during the ENSO episodes. Also, a comprehensive intensity index reflecting both oceanic and atmospheric features was generated.Furthermore, they are also analyzed and discussed for the ENSO duration,intensity, pattern and onset characteristics.