There are many unconformities in the Tianshan Mountains and adjacent areas since the Mesozoic, among which the unconformity at the base of the Lower Cretaceous is the largest regional unconformity throughout the whole area. The studies on the chronology of detrital zircons from Mesozoic- Cenozoic sedimentary strata and their source areas have shown that there are a large number of late Mesozoic magmatic zircons in the detrital materials, indicating a certain amount of magmatic activity in the area during this period. This study suggests that the late Mesozoic tectono- magmatic events mentioned above represent the Yanshanian Movement in the Tianshan Mountains and adjacent areas. Unconformities at the base of the Lower Cretaceous overlap the underlying pre- Cretaceous strata. The stratum development, denudation degree and tectonic deformation intensity under the unconformity vary in different areas. In the present Tianshan Mountains, the Lower Cretaceous directly overlies the Middle Jurassic Toutunhe Formation, while the Upper Jurassic Qigu and Kalazha Formations are totally missing. In the Tarim, Junggar and Tuha basins on both sides of the Tianshan Mountains, the Upper Jurassic are locally developed and their ranges are much smaller than that of the Middle and Lower Jurassic. Further study found that the Upper Jurassic strata in the basin are usually developed as growth strata at the limbs of the fold paleouplift formed in the late Mesozoic. Based on previous zircon U- Pb ages of tuff beds in the middle- lower part of the Upper Jurassic Qigu Formation and biostratigraphic data, the initiation time of the Yanshanian Movement in Tianshan and adjacent areas has been limited to approximately 160 Ma. The Yanshanian tectonic deformation in the Tianshan Mountains and adjacent areas has multiple directions. It is possibly related to the superimposed effects of tectonic events such as the collision between the Lhasa block and the southern margin of Asia, the closure of the Mongolia- Okhosk Ocean, and the continent- continent collision between the Kolyma- Omolon block in northeastern Russia and the Siberian craton since the late Middle Jurassic. This is also a concrete manifestation of East Asia multi- plate convergence during the late Mesozoic in the Tianshan Mountains and adjacent areas.