The paleoclimate and sedimentary environments of the Jurassic in northern margin of Qaidam Basin are analyzed according to the paleoecology on multiphylum fossils, lithofacies and sedimentary structures. The characteristics of fossils such as ostracoda, charophytes, conchostraca, bivalves and plants indicate that the sedimentary environments at that time were mainly marshes and shallow shore-lakes. The fossil assemblages of plant and sporopollens indicate that the paleoclimate was a warm and humid climate of the tropic and subtropical zone and became drier and warmer twice in the Early and Middle Jurassic in northern margin of Qaidam Basin. The alternative occurrence of terraneous plant fossils and animal fossils represents a paleogeographic feature with the intra-distribution of lakes, marshes and low hills. The Early Jurassic lakes were developed for many times, but with a smaller scale. Lake area expanded to the largest in the late-middle Middle Jurassic.