Research on paleo-productivity has received much attention because of the possible link between atmospheric CO2 concentration and organic productivity in the oceans. It has been found that the changes of paleo-productivity in the WEP,which could be indicated by the ln(Ba/Ti) and ln(Ca/Ti) ratios, displayed clear glacial-interglacial and processional cycles during the last 370 ka. The average value of ln (Ba/Ti) ratio was 13 % higher during interglacial stages than during glacial stages, indicating that the paleo-productivity was high during interglacial stages and vice versa. Moreover, the δ18 O difference between surface dwelling species G.ruber and thermocline dwelling species P.obliquiloculata, Δδ18 O(P-G), which was usually interpreted to reflect changes of the thernocline depth, fluctuated around 1.0 ‰ throughout the past 370 ka without a clear glacial-interglacial pattern.