Abstract: Danxia landform is widely developed in southern China, and its red feature is one of the main distinguishing marks of landform. Previous research results have shown that the red color of Danxia landforms is related to iron in the strata, but no in-depth study has been conducted on the state of iron occurrence. In this paper, the mineral composition, geochemistry and iron occurrence of samples from Danxia Mountain in Guangdong Province and Longhu Mountain in Jiangxi Province are studied. The results show that: (1) The Danxia landform stratigraphic samples in Guangdong Province and Longhu Mountain in Jiangxi Province show that the main mineral composition is quartz and feldspar, containing a small amount of clay and iron oxides, with a high degree of consolidation, and some layers contain gravel. (2) Geochemical analysis shows that the content of SiO₂ in both is the highest, followed by Al₂O₃. The content of TFe₂O₃ (0.81-1.63wt%) and FeO (0.08-0.16wt%) is lower, indicating that the content of iron minerals is not the main factor causing redness. (3) The iron in the Danxia Formation of Danxia Mountain in Guangdong and Longhu Mountain in Jiangxi mainly exists in the form of clay iron and oxide iron, among which trivalent iron ions (oxides-Fe³⁺41.3% and 44.3%，clay-Fe³⁺49.7% and 47.6%) are much higher than the content of divalent iron ions (clay-Fe²⁺9.0% and 8.1%). All indicate that the content of iron in the Danxia Formation is relatively low, but it may be in the form of an iron oxide coating that exists on the surface of minerals such as quartz and feldspar, causing the formation to appearred.