The obvious conformability of basinmountain topography with the crustal structure in northwestern China is an important characteristic of current basinmountain tectonicsIn this paper，we discuss the palaeogeographical appearances and the process of the development and evolutionin different periods of the MesoCenozoic in basinmountain area in northwestern ChinaBased on their evolutionary process since the Mesozoic，we know that，there were different palaeogeographical features in different periods of the MesoCenozoic，and they continuously developed with the tectonic evolution of the crust and the upper mantleThe basinmountain tectonics was controlled by the activities and evolution of crustUsually，the main mountains in northwestern China are thePaleozoic or the Early Mesozoic orogenic zones，but the formation of such huge mountains happened in the Late CenozoicThe tectonic evolution history of Tianshan is an exampleIn the Triassic，it was once uplifted to form the mountains with thick molasse accumulation on both its sides，Junggar and Tarim BasinsThen it became a peneplain by the exposion and deplanation in the Jurassic，forming the widespread coalbearing strata which can be correlatedFrom the Cretaceous to the Early Cenozoic，it was uplifted again，until the Quaternary to build huge mountains with two large sedimentary basins on both sidesThere were similar development and evolution histories for other mountains in northwestern China，such as Qilian and Kunlun mountainsAt last，the basic factor controlling the process is the tectonic evolution of the crust，even of the whole lithosphere in this region