The pedogenic carbonate nodules formed during the Holocene in the Wugong section on southernmost Loess Plateau were selected to study the mineralogical and acid-leachable elemental composition of carbonate nodules together with the specific properties including grain size and distribution of organic matter and carbonate in ＞250 μm, 50-250 μm and ＜50 μm nodules, to understand the formation of carbonate nodule and assess its elemental enrichment characteristics. The results showed that the pedogenic carbonate nodules were cemented by mainly ＞250 μm and ＜50 μm nodules. Pedogenic carbonate first deposited on the surface of clay and fine silt and then soil pores between the grains were gradually filled by pedogenic carbonate along with the deposition resulted in the formation of carbonate nodules and continued growing. The carbonate content in the nodules increased sharply with the increasing size of nodules and consequently diluted and decreased the organic matter content. The grain composition became coarse and the content of clay minerals decreased with increasing size of carbonate nodules. Elemental composition of the acetic acid-leachable fraction in each size of carbonate nodules was characterized by extremely high Ca concentration (61.03-207.36 g/kg) directly related with carbonate content. It is indicated that calcium carbonate was the dominant form of carbonate in the nodules. The acetic acid-leachable fraction is composed of certain amounts of Si (8.90-10.70 g/kg) and Al (2.78-5.06 g/kg) from amorphous phases of pedogenic origin, K (3.34-4.32 g/kg) and Mg (2.22-3.64 g/kg) from clay minerals, and a small amount of Na (0.70-0.85 g/kg) from highly soluble salts.