Based on the quantitative statistical analysis of benthic foraminifera fauna in 255 samples that were taken from three boreholes (GK138, GK111, GK95) of the Laizhou Bay of Bohai Sea, 15 genera and 32 species of benthic foraminiferal fossils are identified. Species richness and diversity of benthic foraminifera and age data of AMS14C and OSL, show three marine sedimentary beds, which can be respectively interpreted as Marine Bed 3(M3) deposited in the Later MidPleistocene phase, Marine Bed 2(M2) in the Late Pleistocene phase and Marine Bed 1(M1) in the Holocene phase in ascending. By the comparison with the global sealevel change curve, M3, M2 and M1 have a good correspondence with the high sea stage of MIS (Marine Isotope Stage) 7, MIS 5 and MIS 1. The analysis results of thickness and elevation of roof and floor in the marine sedimentary beds show that the multistage and the different intensity of tectonic activities occurred from Later MidPleistocene to Late Pleistocene, and tectonic activity was relatively weaken in the Holocene. Three microfossil assemblages related to different environments were identified based on multivariate quantitative analyses (mainly Qmode cluster analysis and principal component analysis): assemblage Ⅲ is characterized by a river mouthsupratidal or paralic environment or a relatively small scale of Later MidPleistocene transgression, assemblage Ⅱ was the product of the Late Pleistocene transgression and indicates a intertidalsubtidal environment, and assemblage Ⅰ is characterized by the supratidalintertidal environment, which mainly occurred during Holocene marine transgression.