Rb and Sr tend to disperse in different minerals, and they are significantly different in geochemical behavior under the Earth surface conditions, which makes Rb/Sr ratios of natural records used as a proxy of paleoclimate change. Under natural conditions, lake sediments include two material sources. One is the terrigenous debris directly caused by physical erosion, existing in the sediments mainly as the residual (detrital minerals) form. The other is dissolved substance caused by chemical weathering in the catchment, depositing in lake sediments through physical adsorption, chemical precipitation and biological uptaking, existing in the sediments as the non-residual (exchangeable, carbonate, Fe-Mn oxide and organic fraction) form. Rb and Sr of various forms record different environmental processes and information. It would exert effect on the accuracy of the research result to use Rb/Sr ratios of bulk sediment samples to reflect paleoclimate/paleoenvironment change. Especially in the catchment, where the changes of physical weathering and chemical weathering are inverse, it would cause confusion or even misreading of the result to use Rb/Sr ratios of bulk sediment samples to reflect paleoclimate/paleoenvironment change. However, it can effectively solve these problems and provide comprehensive information on the physical removal and chemical weathering in the catchment to carry out the study of Rb/Sr ratios of different forms of lake sediments: Nonresidual Rb/Sr ratios reflect the chemical weathering in the basin, for relatively coarse resolution (10a international) research; and residual Rb/Sr ratios reflect watershed physical removal, for annual or even higher resolution.