Four sections of dolomite, grainstone, micritic limestone and granulir micritic limestone in Dawangou of Keping area are selected, and their structural fractures are statistically analyzed. The results of fracture density measurements show that the value of the fracture density from big to small is dolomite, grainstone, micritic limestone and granulir micritic limestone, which means in the same tectonic setting dolomite is easier to produce structural fracture. Also, the purer and the bigger granules the carbonate have, for example limestone, the more difficulty to produce structural fracture. The relationship between the structural fracture and the rock mechanics parameters is discussed.