Trace content of Cu, Zn, Cd and Fe in bones is determined by flame atomic absorption spectrometry after preceding preconcentration using the extraction system O-phenanthroline-sodium perchlorate/1, 2-dichloroethane. Also, the factors of influence were studied. The method was simple, accurate and reliable, The detection limits were Cu: 0.038microg/ml, Zn: 0.0042microg/ml, Cd: 0.0019microg/ml, Fe: 0.02microg/ml. The recovery rate was between 92.8 and 105%.