Abstract: In Beijing plain area the tectonic settings during the Tertiary period having an upheaval in its northwestern part, a depression in its central part and Dai Xing upheaval suffered remarkable changes in the course of recent tectonic movement. From the repeated levelling data it is suggested that along the NW trending Nankou-Sunhe fault was generated a subsidence zone cutting across the NE trending Tertiary structure and destroying the original tectonic framework.In connection with this the recent strain field also shows an obvious change. From the deformation tendency plot compiled on the basis of repeated levelling data the long axis of contour lines takes the direction from nearly east-west to north-west-west reflecting a tensile direction on the earth’s surface. Further triangulation surveys indicate that the tensile direction is south-east, the compression direction is north-east in the Beijing plain area. The tensile strain amounts to 2.5/10^-6, while the compression strain is 0.8/10^-6, much lesser than the former.Some faults in this area have showed anomalous activities before the Tangshan earthquake. During the period of 1973-1976, six faults have a tendency of increasing or reversing activities, but in 1976, four of them rebounded to the same situation as in 1973. It is preliminarily belived that the activities of these faults may be related to the 1976's Tangshan earthquake.

摘要： 从测量资料的研究得知北京平原地区的现代构造形态与第三纪形成的京西北隆起、北京凹陷、大兴隆起等不相符合。由于出现一个北西向的下降带,使原来“两隆夹一凹”的构造形态可能解体。同时,应变场也起了变化,认为该地区目前处在南东方向的拉伸应力场中。