Tremendous changes have taken place for rivers

lakes and coast line in the North China plain over the centuries. Study on changes of these water area have great significance for water resource exploitation

land use planning

industry and agriculture.We can recognize the trace of water area change more quickly and correctly than conventional method by using multi-times and multi-types remote sensing data making process of image match and enhencement with computer and optical equipments. Mean while

the features of water area changes in ancient time can be recovered through comparing Landsat data and air-photo with the history materials.Remote sensing technique is very efficient for monitoring quantitative changes of water area in shortterm. The study in this paper shows that since 1855

a piece of land has been formed in Yellow River delta at the rate of 23.7 km2/year

and the water area of Baiyangdian lake went down by about 426km2 from 1960 to 1985.Through systematic analysis on water area changes in this region with remote sensing data

the results show that the frequency of these river changes have become less and less under the control of manpower

the area of lakes has cut down year by year

while the coast line has continually moved towards the sea in the river mouth. The changes of almost the whole water area have been affected by Yellow River activity in ancient time

but mankind have been playing an increasinly important role on water area changes in modern time. For instance

the drying up of Baiyangdian lake is mainly caused by mankind activities

such as increase of water supply for industry and agriculture

a great quantity of reclamation etc.