Abstract: <FONT face=Verdana>Cobalt Chloride Hexahydrate (CoCl2&#8226;6H2O) is a main raw material for preparing cobalt oxide (Co3O4) powder used for lithium cobalt oxide battery.Granularity and dispersion of Co3O4 powder were not the same when crystal water contents of CoCl2 were different.Powders with small size and uniform distribution could be obtained with CoCl2&#8226;2H2Oas raw material by high temperature hydrolysis method.Dehydration process of CoCl2?6H2O was determined by TG-DTA.In addition,effects of drying temperature and thickness of feed layer on dehydration in the dehydration process were studied and analyzed,which provided the theoretical foundation for preparation of Co3O4 with CoCl2&#8226;6H2O as raw material by high temperature hydrolysis reaction.Results indicated that higher temperature and thinner feed layer both could increase dehydration speed of CoCl2&#8226;6H2O;four crystal waters were dehydrated from CoCl2?6H2O and it turned to CoCl2&#8226;2H2O at 120 ℃ for 230 min;another one crystal water was dehydrated and it turned to CoCl2&#8226;H2O at the same temperature for 360 min;If the temperature increased to 220 ℃ for 21 h,all crystal waters could be dehydrated.</FONT>