The Lower Paleozoic in northwestern Ordos Basin belongs to Qilian marine sedimentary province, in which Carbonate platform margin is inferred to be present from regional geology. Previous drilling confirms that there may be reef-bank facies in carbonate reservoir in Kelimoli Formation. However, the seismic attributes and distribution scale of the reef-bank facies in this area are not fully recognized. Based on known seismic attributes of reef-bank facies and experience of external exploration area, it is summarize that the seismic attribute of reef-bank facies is mainly hummocky reflection with relative strong attributes. Several technologies such as seismic facies analysis, seismic attribute analysis and seismic inversion are applied to predict the distribution of reef-bank facies in the study area. The actual data shows that in Qitan 1 well there are bioclastic limestone, algal limestone and sandy sparite limestone in Kelimoli Formation, and there are indications of gas-bearing property.