Abstract: A mixing model of uranium-series method based on Th230/U234 and U234/U238 ratios for the sediment of Peking Man eave is discussed here. The resulting ages of fossil bones collected at the Loe. 1 are determined as follows: about 230 X 108 yr B.P. for the lst-3rd layers, 350 X 103 yr B.P, for the 6th-7th, over 400 X 103 yr B.P. for the 8th-9th, and more than 500 X 103 yr B.P. for the 12th.
In an attempt to explain the discordant isotopic ratios of a suite of bone samples from Peking Man eave, the author is of the opinion that the paleohydrological condi_x001F_tions in the environment changed during the last 200 X 103 yr, so did the migration processes of uranium concentrations. Hence fossil bones for uranium-series method have indeed commanded much attention.

Key words: Uranium-series dating; Mixing model; Fossil bone; Peking Man