The D and O content of Yangtze River water collected once a month for a one year period at Wuhan, Nanjing, Shanghai has been determined mass spectrometrically. Seasonal variation has been observed within the range δD = 30--40 and δ18O = 4--6.5 with the lowest value in October and the highest in May. The correction between 3D and δ18O is:δD=7.01 δ18O-1.94.