Abstract: Using CoCl₂ solution as cobalt source and ammonium oxalate as precipitant, the affects of microwave on morphology of synthesis cubic-Co₃O₄ and its precursor in the liquid phase were studied. The precursor and thermal decomposition productswere characterized by scanning electron microscope(SEM), x-ray diffraction(XRD) and thermogravimetric-differential thermal analysis(TG-DTA). The effects of heating method, initial concentration of CoCl₂, reaction temperature and reactiontime on the morphology and the size of the precursor are detected.The results show that the cubic-Co₃O₄ precursors are produced, their average particle size are about 3 μm, under the condition: the initial reactant concentration is 0.1 mol/L, The reaction temperature is 80 ℃ and the reaction time is 150 minutes.