Large-scale of mafic dyke swarms are widely distributed in Kuluktag region in Xinjiang, NW China, which indicates maguvttic thermal events and crustal extensional events. Based on multisource high-resolution remote sensing images (Landsat 7 ETM + .SPOT, CORONA KH-4B, QuickBird2 ), we extracted 2284 dykes to analyze the geometric feature and to estimate the magma overpressures. The exposed dykes mainly intruded Neoproterozoic intrusive rocks, Precambrian sedimentary rocks and metamorphic rocks. The results show that the NW (300° ~320°) dykes dominate,followed by the NE (40°~ 70°) dykes and nearly EW-trending dykes. With a mean value of 4. 3km,the length of dykes ranges from 90m to 22. 8km and is statistical law with log-normal. According to 4 section lines of NE-trending (60°) ,the crustal extension are 4. 22% ,1.83% ,2. 60% and 7.40% from north to south. Using the aspect (length/thickness) ratios of the dykes, the magma overpressures at their time of emplacement are estimated. Most values indicate overpressures between 7. 9MPa (E = 10GPa) and 23.7MPa (E = 30GPa). The dyke swarms appear to be two ages of Neoproterozoic and Permian in this region, the spatial distribution of which is closely related with granites. These dyke swarms have experienced several tectonic and deformation events, and are likely to be the results of various tectonic background.