The Intergovernmental Panel on Climate Change(IPCC) produces periodic assessment of the future climate due to increasing green house gases (GHGs). The coupled climate models participating for 4th Assessment Report of IPCC (AR4-IPCC) have diverse characteristics of ENSO simulation. In particular, previous studies have been investigated in terms of spatio-temporal structure of ENSO variability in IPCC coupled general circulation models (CGCMs) for current climate. This study classifies the IPCC-coupled models into regular and irregular period types. The 20th-century climate simulations analyzed this study has been obtained from the Program for Climate Model Diagnostics and Intercomparison (PCMDI) data archives. Multiple simulations are obtained for the same period from each model during 1900 - 1999. The investigated intercomparisons have been performed using 23 climate models. The dominant modes of the tropical upper ocean temperature of the regular and irregular models are different from each other. In particular, the irregular models exhibit a strong ENSO variability in the central Pacific near the dateline.