The gas shales within the Shanxi Formation were deposited in the interdistributary swamps, levees, distal crevasse splays and small lakes environment of delta plain at the northern Ordos Basin. The accumulation conditions and favorable area optimization of the Shanxi shale gas were investigated based on analysis of organic geochemistry, petrophysics, gas content and lithology with data of drilling, gas logging and wireline logging and depositional setting research. The shales have relatively high total organic contents with average of 5.28% in the Second Member of the Shanxi Formation (Shan2 horizon) and 3.02% in the First Member (Shan1 horizon), high organic maturity with average Ro of 1.89% and organic matters are dominant in typeⅡ2、Ⅲ, which indicates good gas generation conditions. The Shanxi shales have average porosity of 1.7%, permeability of 0.0415mD and gas content of 0.64 m3/t, and the thickness of single shale layer is relatively small and interbeded with tight sandstones and coals vertically with large added shale thickness (up to 75m on average). These imply that the shales have rather good permeability but inferior storage capability. Brittle mineral content of the shales is 49.9% on average, and clay content is comparatively high (average of 50.1%) with low shale gas resource abundance; however, the shales are buried at depth less than 3000m, and have acquired production of 6.4 thousand cubic meter per day by fracturing, which infers a good shale gas potential. Total organic content of the Shan2 horizon is higher than the Shan1 and gas content higher than the Shan1, which indicates that the shale gas is more enriched in Shan2 horizon than in Shan1. Favorable areas of the Shan2 horizon predicted principally from shale thickness and depositional setting distribution show ribbon shapes mostly trending northeast to southwest or north to south, which were governed by interdistributary swamps microfaces of delta plain.