In the coastal plain of Laizhou Bay, the thickness of Quaternary sediments increases from the south to north and from east to west. The center of sediments is in the coastal area of the Xiaoqing River mouth. The contribution of marinebstrata is very different in the west and east, showing differences between the relief and sea level height during different stages. There were two transgressions east of the Weihe River in 40, 000 a. B P, three west of it in 100, 000 a.B P. and five in the west of Laizhou Bay in 200, 000 a. B P.. The Ostracean reefs of China in the middle Holocene were discovered for the first time in Xinhe of tbis region. This leds to the discovery of the Xinhe Paleo-coastline, high sea level in the middle Holocene and warm Paleo-marine environment so that the ancient Ostracean reefs have become the important indicators for resonstruction of the ancient coastal environment. The underground Quaternary littoral facies brine and widely distributing loess are due to the special geographical environment. Conversely, they are indicators of the environment in the ancient climate. The loess platean reflects the dry climate in this region in late Quaternary. During the cold climate period of late Pleistocene. in this region, there were forest-grassland vegetation and animal groups existing in the outer surroundings of the ice margin. This period is the important stage of the ancient environment evolution in Shandong Peninsula.