Interannual variations of Pacific North Equatorial Current(NEC) transport during easternPacific El Ni?os(EP-El Ni?os) and central-Pacific El Ni?os(CP-El Ni?os) are investigated by composite analysis with European Centre for Medium-Range Weather Forecast Ocean Analysis/Reanalysis System 3.During EP-El Ni?o,NEC transport shows significant positive anomalies from the developing to decay phases,with the largest anomalies around the mature phase.During CP-El Ni?o,however,the NEC transport only shows positive anomalies before the mature phase,with much weaker anomalies than those during EP-El Ni?o.The NEC transport variations are strongly associated with variations of the tropical gyre and wind forcing in the tropical North Pacific.During EP-El Ni?o,strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean,lowering the sea surface height and generating a cyclonic gyre anomaly in the western tropical Pacific.During CP-El Ni?o,however,strength of the wind and associated Ekman pumping velocity are very weak.Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Ni?o. Interannual variations of Pacific North Equatorial Current (NEC) transport during the eastern Pacific El Niños (EP-El Niños) and central-Pacific El Niños (CP-El Niños) are investigated by composite analysis with European Center for Medium-Range Weather Forecast Ocean Analysis / Reanalysis System 3.During EP-El Niño, NEC transport shows significant positive anomalies from the developing to decay phases, with the largest anomalies around the mature phase. Duration CP-El Niño, However, the NEC transport only shows positive anomalies before the mature phase, with much weaker anomalies than those during EP-El Niño. The NEC transport variations are strongly associated with the tropical gyre and wind forcing in the tropical North Pacific. During EP-El Niño strong westerly wind anomalies and positive wind stress curl anomalies in the tropical North Pacific induce local upward Ekman pumping and westward-propagating upwelling Rossby waves in the ocean, lowering the sea surface height and generating ac yclonic gyre anomaly in the western tropical Pacific. While CP-El Niño, strength of the wind and associated Ekman pumping velocity are very weak. Negative sea surface height and cyclonic flow anomalies are slightly north of those during EP El Ni? o.