Abstract: A method for rapid separation of Os by direct distillation with Carius tube is described in this paper. Using Carius tube to replace the traditional distilling flask has remarkably improved the separation efficiency of Os and saving the reagents. The parameter of Carius tube distillation was optimized and gas flow rate of 30～80 mL/min and 30 min distillation time were selected. The method has been applied to ReOs dating by inductively coupled plasmamass spectrometry (ICPMS). The dating results obtained from molybdenite reference materials GBW 04435（HLP） and GBW 04436 （JDC） are (221.3±0.4) Ma (n=7) and (139.7±0.2) Ma (n=2) respectively, in good agreement with certified values of (221.4±5.6) Ma for GBW 04435 and (139.6±3.8) Ma for GBW 04436. The method has a good application prospects in the conventional ReOs isotope analysis.