Abstract: The middle pleistocene laterite bed was discovered on the surface of terraceⅤor above and on the belting denudation plane of terraceⅡ. According to the data of ESR and the 14 C isotope age as well as the result of the correlation of stratigraphy, ice period and deep sea oxygen isotope, the age of the laterite is 150～185 ka, which makes it possible to correlate it with the late Pleistocene reticulate laterite of Sichuan Yunnan regionally.The middle pleistocene laterite bed will be named as Wusiding laterite bed, formed in hot and humid environment of a wide valley, with an altitude of no more than 2,000 m above sea level. Now the altitude is more than 2,890 m, so the areas have been uplifting rapidly since the late Pleistocene,with an average speed of 5.9 mm/a, which makes the hot and humid air weaken, and climate and environment tend to become worse and worse.