Abstract: Benthic foraminiferal assemblage in the three cores taken from the northern Yellow Sea muddy area during 2006 were analyzed for reconstructing environmental evolution. Data show that the marine environment of the study area has been strongly influenced by the Post-glacial transgression process and the fresh water input of adjacent rivers. The variation in benthic foraminiferal assemblage could be divided into three stages since 13.7 cal.kaBP:Eurythermal and euryhaline species dominated the fauna during 13.7~9.2 cal.ka BP, denoting a littoral environment with low temperature and low salinity; E. magellanicum became the absolute imperium during 9.2~5 cal.kaBP, denoting the anoxic but nutrient environment strongly influenced by the great runoff input; B.frigida and P.turberculacum took the dominant position after 5 cal.kaBP, indicating the affect by the marginal cold water from the northern Yellow Sea.