Abstract: <SPAN lang=EN-US style="FONT-SIZE: 10.5pt; FONT-FAMILY: "Times New Roman"; mso-bidi-font-size: 12.0pt; mso-font-kerning: 1.0pt; mso-ansi-language: EN-US; mso-fareast-language: ZH-CN; mso-bidi-language: AR-SA; mso-fareast-font-family: 宋体">By means of microwave cavity perturbation,pad value and relative frequency shift of specturm before and after adding raw materials<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>were analyzed and microwave-absorbing characteristics of basic cobalt carbonate,cobalt oxide (Co<SUB>3</SUB>O<SUB>4</SUB>),and their mixture were investigated.Meanwhile,temperature rise behavior of the samples under<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>microwave heating was discussed.Research results showed that Co<SUB>3</SUB>O<SUB>4</SUB> had strong capability to absorb microwave energy,while basic cobalt carbonate was a relatively poor microwave absorber.Capability to absorb microwave energy of the mixture increased with an increase mixture ratio of Co<SUB>3</SUB>O<SUB>4</SUB>.When microwave irradiation time was 110 s under power 820 W,the temperature of<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>the mixture with mixture ratio 20% of Co<SUB>3</SUB>O<SUB>4 </SUB>just can reach<SPAN style="mso-spacerun: yes">&nbsp; </SPAN>375 K.Temperature rise speed of the sample was in proportion to specific power.Research results of temperature rise behavior was in good agreement with the test result of microwave-absorbing characteristics.It is feasible to prepare Co<SUB>3</SUB>O<SUB>4</SUB> by calcination from basic cobalt carbonate in microwave field.</SPAN>