Inversion of climate and paleoenvironment using gamma ray (GR) log is being highlighted and improved increasingly in the world. Application of inversing paleoclimate change before 2.85 Ma has been succeeded in Quaternary in Qaidam basin. This paper shows gamma ray log is an important parameter for paleoclimate research, making an analysis of paleoclimate and paleosedimentary environment combining gamma ray log with sporopollen data and other geological data from two wells in Quaternary Qaidam Basin. Both Value sizes of GR and dry/wet changes of paleoclimate have internally related to the depth of dipositional water body. Quick/slow variations of frequency and amplitude of GR log show relatively active and stable characteristics of sedimentary environment. For this, specific analysis to an evolution of sedimentary environment from the two wells was made. Integrating paleoclimate with sedimentary environment, abnormal varying of GR curve is of a special implication in sedimentary facy. Variations on tectonic -paleogeography background could change the corresponding relation which is characterized as a general regularity by a synchronization of the GR log value-increasved, the paleoclimate-wetting, and the depositional water-deepen. Therefore, information of researching a paleogeography development can be presented, enriching a geological implication of GR log investigation further. This demonstrates GR log is a significant indicator in studying of the Jurassic paeoclimate and paleoenviroment.