Abstract: The North Pacific Oscillation (NPO) and East Asian Winter Monsoon (EAWM), as significant extra tropical climate modes, have meaningful impacts not only on the climate of China and even the entire East Asia, but also on the global scale system of ENSO. With HadISST re-analysis data and NECP-NCAR monthly mean atmospheric circulation and precipitation data, this paper analyzes the different influences between winter NPO and EAWM on the ENSO of following winter, and the possible mechanism of the differences with statistical methods. The results show that the effects of winter NPO and EAWM on the subsequent winter ENSO are significantly differences, both in correlation and the intensity of the ENSO triggered. Further the evolutionary features of sea surface temperature (SST) anomalies, 850 hPa winds and precipitation obtained by correlation and regression upon the normalized winter NPO and EAWM indexes are studied. It shows that in the tropical Pacific region, winter NPO and EAWM have established corresponding responses by stimulating westerly winds and precipitation anomalies in the western equatorial Pacific region. The positive air-sea feedback mechanism and the difference in strength and location of this positive-feedback mechanism causes different influences on ENSO. Besides, different interdecadal variations of NPO and EAWM in winters may be another reason.