The estuary runoff of the Yellow River decrea sed during the late 20th century and its lower course became dry many times.Besi des its obvious effect on ecology development and especially on agriculture prod uction,speoial attention should be paid to the fact that the  amount of transpo ttd sediments also decreased obviously along with the runoff decreasing thus led ding to the sharp reduction of continentbuilding area of the estuary since the 1990s.The continentbuilding stopped and marine transgre ssion occurred during 1996 and 1997.Among a series of ecological environmental  problems resultmg from the decreasing of estuary runoff and amount of  transpor ted s ediments of the Yellow River,the decreasing of continentbuilding area and the transgression of ocean water may be related with the future of the Yellow River Delta and may endanger the safety of  the Shengli Oilfield at present.thus
a great attention should be paid.Checking the changes of ecological environments by geophysical logging techniques is also discussed in the paper.