采用色度学方法，系统研究了下蜀黄土典型剖面的反射光谱特征。结合磁化率、微量元素Ｒｂ、Ｓｒ的含量和比值，讨论了色度参数的古气候意义，初步把下蜀黄土形成以来的古气候划分为３个波动旋回。丁蜀黄土和黄土高原色度参数的对比，揭示了长江中下游地区更强的化学风化作用和成壤强度。 By using the method of colorimetry, the reflection spectral characteristics of the typical sections of Xiashu loess were systematically studied. Based on the contents and ratios of magnetic susceptibility, trace elements Rb and Sr, the palaeoclimate significance of chromaticity parameters was discussed, and the paleoclimate since the formation of Xiashu loess was divided into three cycles. Comparisons of the chromatic parameters of Dingshu loess and the Loess Plateau reveal stronger chemical weathering and soil-forming intensity in the middle and lower reaches of the Yangtze River.