Abstract: The Core SYS-0803 was taken from the northwestern South Yellow Sea (35°02' N,121°45' E,water depth 49.00 m, core length 60.30 m), and it recorded the paleoenvironmental changes of the past~140 ka. Q-mode factor analysis was carried out for 248 samples and 25 benthic foraminiferal species, and 4 varimax factors were selected, which account for more than 93.0% of the total variance. Based on the benthic foraminiferal assemblages, four marine and four terrestrial strata were recognized in this core. The late MIS 6 marine layer (depth 53.06~50.28 m) contains typical warm-water benthic foraminifera, implying the occurrence of a warm current. The MIS 5e (depth 33.76~30.55 m) marine layer was remarked by the abundant cold-water benthic foraminifera and ostracods, indicating the development of a strong cold-water mass similar to the modern Cold-water Mass of the Yellow Sea. A short regression (depth 13.80~12.91 m, 12 460~11 572 cal.aBP)was found in the postglacial transgression layer, probably responding to the Younger Dryas event.