Haematite (α-Fe₂O₃) and goethite (α-FeOOH) are two chromogenic minerals commonly found in aeolian sedimentsand soils. They are important indicators of environmental change. Haematite indicates dry and hot environmental conditions, while goethite indicates wet and cold environmental conditions. They compete with each other and coexist in sediments and soils. In practical research, the ratio of goethite to haematite is used to indicate changes in environmental conditions. Due to the low content and weak magnetism of haematite and goethite in natural samples, traditional methods, such as X-Ray diffraction, chemical analysis and rock magnetism, have difficulty accurately and conveniently detecting their contents. Based on their optical characteristics, an increasing number of researchers have tried to quantify haematite and goethite in natural samples using diffuse reflectance spectroscopy and chromaticity methods in recent years. There are some differences between these two approaches. The intensity of the characteristic peaks of haematite and goethite in the diffuse reflectance spectrum is affected by the substrate effect, lattice ion substitution and other factors. The redness (a^*) of the chromaticity parameter is also affected by lattice-ion substitution, and the factors affecting the yellowness (b^*) are more complicated. Therefore, the relevant parameters of the two methods cannot be simply equivalent to the content of haematite or goethite. It is particularly important to compare the two approaches. In this study, we use diffuse reflectance spectroscopy and chromaticity to conduct experiments on three aeolian sedimentary profiles: Bole, Xinjiang, in an arid region; Jinchuan, Sichuan, in a subhumid region; and Xuwen, Guangdong, in a humid region; to analyse the indicative significance and applicable range of different parameters for haematite and goethite and to discuss the environmental significances of the ratio of goethite to haematite. The results show that diffuse reflectance spectroscopy and chromaticity methods effectively identify the signals for goethite and haematite in aeolian sediments. However, due to the complex influencing factors, they can only be used as semiquantitative indicators in a large range of space. a^* can better indicate haematite content; Gt/Hm and b^*/a^* can also better reflect the ratio of goethite to haematite; but Gt and b^* cannot indicate well the content of goethite. Atmospheric hydrothermal conditions cannot be completely equal to soil hydrothermal conditions, atmospheric precipitation does not completely enter the soil, temperature affects the moisture content in the soil through evaporation, and the hydrothermal condition of the soil is affected by many factors. Temperature determines the rate of chemical reactions on a large geographic spatial scale, and the effect of temperature on the formation and preservation of haematite and goethite is greater than that of precipitation.