Based on the researches on Li, Rb, Sr and Ba concentrations and Li/Ba and Rb/Sr in two sediment cores of the Bohai Bay, the vertical variations of Li, Rb, Sr and Ba concentrations in recent hundred years were studied, the covariation patterns of Li/Ba and Rb/Sr were found, and the environmental change indications of Li/Ba and Rb/Sr to the coastal waters were revealed in this paper. The results suggested that the Li and Rb concentrations increased with depth during 0~20 m in core A2 and A6, whereas the Sr and Ba concentrations decreased with depth. Surprisedly, the vertical distributions of Li/Ba and Rb/Sr displayed covariation characteristic in recent one hundred years, that was, Li/Ba and Rb/Sr increased with depth in core A2 near the Haihe Estuary whereas those in core A6 off the estuary increased with depth during 0~15 cm (corresponding to 1963~2008 years) and then remained stable below 15 cm (corresponding to 1900~1963 years). In conclusion, the changes of Li/Ba and Rb/Sr affected by marine processes mainly occurred in recent 45 years. Li/Ba mainly reflected the deposition process change of riverine sediments entering the Bohai Bay; however, Rb/Sr dominantly reflected the chemical weathering history of original sediments and indicated climate change of source region. In core A2, the minimum value of Li/Ba appeared in 20~22 cm (corresponding to 1930s) and 10~20 cm (corresponding to 1960s), according with the floods of the Haihe River in the years of 1939 and 1963. Rb/Sr decreased with depth during 0~12 cm in both cores, according with the temperature increase during early-1970s to 2008.