Abstract: In this paper, the synoptic case of July 11-14, 1957 is selected for computation. of water vapour transport ovor Eastern China.Dwring tliis period heavy precipitation has causod flcod ov er lower Yollow River area,. Tho flux of wator through the cross sections along the 105° and 120° meridians and 26°, 31°, 36° and 42° latiirudes are computed. The triangle method,with side length of 200 krn, is used for the computation of convergence and divergence of water vapour flux. The results are checked with the observed precipitation distribution. It is found that the accuracy of computation is reasonable.Same computations are also conduct.cd for daily situations. From theca computations, it is lean that even if the tvind velocity incraases rapidly with haight in the troposphere, the vator transport in the Iotvar levels is still of much more importance. It shows also that the land is a source of water vapour for the atmosphare.