Abstract: Based on the instrument measured data in the past 50 years and the data extracted from historical documents, a study has been made of the human activities on the river mouth extension, at a time scale of 10 2～10 3 years. During the period studied, the Yellow River empties into the Yellow Sea and Bohai Sea, successively, and the deltas it has shaped are known as Abandoned and Modern Yellow River Deltas. The extension of the Abandoned Yellow River can be divided into 2 stages. The first is from 1194 to 1578, during which the extension rate of river mouth was rather slow. The second is from 1579 to 1855, during which the extension rate was greatly accelerated. The curve showing the temporal variation of the extension rate of the modern Yellow River Mouth can be fitted by 3 straight lines with different slopes. Accordingly, the change from 1855 to present can be divided into 3 stages, and the turning points between the 3 straight lines may be regarded as the threshold points that indicates the marked changes in the manner and degree of human activities. On this basis, a 3 stage model has been put forward to describe the process of river mouth extension as a response to the changing human activities.

Key words: Historical Process, Human activities, River mouth Extension, The Yellow River