In 1979, some foraminiferal fossiles and diatomaeeous fossiles were discovered by us from the cores of five drill holes in Holocene strata of the southeast coast of Liao-dong Peninsula. The foraminiferal fossiles include Arenoparrela mexicmia Trochammina inflata, Trochammina sp., Miliammina sp. Ammonia sp.. The diatomaeeous fossiles belong to Cosevnodiscus spp.. The new disoovered bed of marine transgression are well developed in the Donggou County of the southeast coast of Liaodong Peninsula, so we called the Donggou transgression. The Donggou transgression correspond to the Tian-jin transgression in N. China Plain, the Changle transgression in S. China (Fujian), and the Flandrian transgression in Europe,Based on the microfossil assemblages, deposited facies change, the Holocene strata in the southeast coast of Liaodong Peninsula have been divided into three formations. They are the Pulandian Formation of Early Holocene, the Dagushan Formation of Middle Holocene, and Zhuanghe Formation of Late Holocene (Table 2, Figure 1).In Upper Pleistocene strata, we discovered some marine diatomaeeous fossiles, such as Coscinodiscus spp., Cyclotella spp., Actinocyclus spp., and some brackish water and fresh water diatomaeeous fossiles, for instance Epithemia sorex, Melosira spp., but these fossiles were only taken from the core of one drill hole at 22.25 meter deep in the Donggou County of the southeast coast of Liaodong Peninsula and have not found in the others. For the purpose of prudence, we have not determined that it is a transgression. This problem is awaiting to study in the future.