The shell bar section of the Qarhan Lake in Qaidam Basin was systematically dated by means of accelerator mass spectrometry (AMS) and conventional radiocarbon dating, and the contrastive analyses of the dating results of various components from different laboratories show that the shell bar section does record the change of high paleolake level of Qarhan (39.7 ka B.P.~17.5 ka B.P.). A series of biomarkers were identified, which included n-alkanes, oxygen-containing organic compounds (fatty acid, n-alkane-2-ones), nitrogen-containing organic compounds (amide, nitrile), polycyclic aromatic compounds etc. The n-alkanes contain very essential information concerning the environment and vegetation during the lake evolution, of which the nC27/nC31 reveals proportionally the evolution of terrestrial woody and herbaceous vegetation, that is, the proportion of woody and herbaceous vegetation changed relatively significantly before the high paleolake level, and insignificantly during the high paleolake level. L/H, nC17/nC31 and nC21-/nC22+ reveal the change of aquatic organisms in the lake, and are more sensitive to climate change than nC27/nC31. There exist fairly good comparability between the appearance of Mollusk Corbicula fluminea in the section and the changes in amplitude and requency of L / H, nC17/nC31, nC21-/nC22 +, nC27/nC31, which must be the consequence of the Collaborative Responses between orbicula fluminea, bacteria algae, terrestrial vegetation and the climate environment. On the basis of observations of biomarkers and Corbicula fluminea fossils, this paper has tentatively revealed the relationship between bacteria algae, terrestrial vegetation and Corbicula fluminea during climate change and confirmed the existence of the high paleolake level of the last glacial period.