Abstract: Basing on the characteristics of regional geological structure of Datong Coal Field, the difinition of the curtian rock (which is a vertical sedimentary vein in coal bed 10 # in Sitai mine of Datong Coal Field), lithologic chracteristics, shape attitude, distribution, and genesis are studied and analyzed in this paper, mean while, It also points out that the curtain rock has genetic relation with para syngenetic karst pillars develped in the mine field.