Abstract: The Paleo-Asian and Paleo-Tethyan tectonic collages in northwest China experienced a complex ocean-continent evolution from the Nanhua period to Paleozoic era, and the continent-continent collisions in Triassic formed the basement to the formation of the intracontinental basin and mountain since the Mesozoic. There are still controversies on the closure and location of the Paleo-Asian oceanic basin and tectonic attribution of the Paleozoic Qin-Qi-Kun orogenic belt. Based on the new geological mapping, and analyses of sedimentary formations, magmatism formations, metamorphism and structural deformations, the Nanhua to Paleozoic tectonic units of northwest China are composed of three oceanic plates, four arc-basin systems and two continental blocks, which can be subdivided into 9 second-order, 46 third-order and 112 forth-order tectonic units. These units could be used to depict the residual compositions of disappeared oceanic basins and marginal accretionary structures of the blocks (lands). Integrated with paleomagnetic and bio-paleogeographical data, we propose the Paleozoic paleogeography reconstructions of northwest China, and discuss the tectonic evolutionary process of oceanic subduction and continental assemblages.