By the worksite investigation over Haihe River mouth it has been discovered that the coliform bacteria have the same distributional feature as that of organic pollution, i.e. the distributional density (or concentration) over the estuary effected by tides is obviously greater than that on the paralic sea outside the river mouth and during the flooding season it is manifestly higher than in ordinary and dry seasons. They came not only from the same source, but also with similar regulation of their changes and migration. Further analysis shows that the quantitative distribution of coliform bacteria vary positively with the variation of content of the main organic pollutants. Therefore it is feasible to use quantitative distribution of coliform bacteria as a pollution indicator organism.