Abstract: The northwestern China (the area west to the Helan Shan-Liupan Shan and north to the Kunlun Shan-Qjnling) occupies an area of 2 million km². It takes the Xiyu System trending NWW and the latitudinal system trending EW as the back bone of the tectonic framework. The Hecynian Movement caused the tectonic system to take shape and develop forward. The Meso-Cenozoic basins are superimposed on different Paleozoic sediments, having oil-generating combinations with multiple series and multiple type of hydro-carbon deposits. Local structures were developed well within the basins. Hundreds of oil and gas shows and 42 oil or gas fields (or deposits) have been found in this area so far. Oil and gas prospect seems to be best in the Junggar, Tarim and Qaidam Basins, being thought as a promising area for the search of giant oil and gas fields. There is also a good oil and gas prospect in the Turpan-Hami, Santang Hu and Gansu Corridor Basins.