Abstract: According to the further study of Yuanmou formation and the comprehensive survey of Lithostratigraphy, paleontological stratigraphy, magnetic stratigraphy, the new tectonic movement of Yuanmou basin and the morphology of human teeth, the age of Yuanmou formation is proved to be early Pleistocene in this discussion.
The locality of "Yuanmou Man"lies at the 25th layer of the fourth member of Yulanmou formation. A further investigation of the strata indicated that the sequence of strata is very clear without disorder. The new study on magnetic strata proved that magnetic polarity column of the fourth member of Yuanmou formation is situated near the Olduvai at the Matuyama reversed polarity epooh, and the age of "Yuanmou Man" is still 1. 70 m. y. B. P. , rather than 0. 50-0. 60 m. y. B. P. as considered by Liu Tungsheng

Key words: Yuanmou Man; Dating; Early Pleistocene