By use of 1948-2000 monthly Northern Hemispheric sea level pressure data,the North Pacific oscillation index(I_NPO) and East Asian winter monsoon index(I_EAWM) are calculated.Results show that the winter I_NPO anomaly bears a close relation to the weather/climate of winter over the mainland of China.When a strong I_NPO occurs,the EAWM will become weaker,and China will experience an extensive high temperature,less rainfall in the middle-lower reach of the Yangtze River;and higher temperature and more rainfall in South China in winter.While a weak I_NPO occurs,EAWM will become stronger,and China will experience an extensive lower temperature and less rainfall in winter.It is also found that when the North Pacific oscillation is strong,the atmospheric circulation shows the weak WP pattern and strong EU teleconnection pattern,and vice versa.