Recently, dolomitic-rock exploration of Junggar Basin has made a sustained breakthrough and opened a completely new exploration field. Definition of dolomitic-rock is concluded, and the effective reservoir type, characteristics of occurrence and formation mechanism of dolomite are determined based on previous research conclusions, core observation, thin section, and so on. The dolomitic-rock with special lithology and limited distribution mainly develops in Permian Fengcheng Formation of Wuxia district of the northwest margin. Overall, the micro-and macro-distribution characteristics of different types of dolomite are different, and their superimposed effect controls the whole features of the present dolomite.