Five tooth samples from the palaeoanthropological site of Jinniushan were dated with both electron- spin- resonance（ESR） and uranium- series techniques. The ESR age of about 230 ka is in good agreement with the U- series dating result

which confirms the hypothesis of possible coexistence of Homo erectus and Homo sapiens in China . Problems in ESR dating are discussed such as :1) inappropriaty of simple exponential extrapolation for accumulated dose determination; 2) experimental measurement of alpha detection efficiency and radon emanation and 3) selection of U- uptake model.