This paper, based on remote sensing data of every four years from 1996 to 2016, uses visual interpretation to extract construction land use information, applies constructed area expansion index, dynamic degree, flexibility coefficient and rate to quantitatively analyze its temporal changes during 1996 to 2016 in Karamay city, and studies its spatial differentiation via fractional dimension, barycenter transfer and compactness. Constructed area expands in forms of “clots, inner filling, star-like and along transportation lines”, varying with stages. Expansion direction changes from southeast, southwest to northeast with barycenter transfer consistent with “three-axis-two-district”. Population size drives such expansion with economic development as its core pushing force. Mineral resources development and modern transportation are vital factors, directed by governmental macroscopic policies, which determine the size and layout of urbanization. Issues such as loose and primitive constructed expansion need to be resolved through spatial extensive controls in order to reach a quality growth.