Nickel-based oxide was prepared by calcination of nickel sulfate,which can be used as raw material for preparation of NiO. With NiSO₄·6H₂O as raw material,the calcination process was analyzed by thermo-gravimetric and differential ther-mal analysis（TG-DTA） and the product was characterized by X-ray diffraction（XRD）.The results showed that the calcina-tion process of NiSO₄·6H₂O can be divided into three stages.The first stage（27~250 ℃） and the second stage（250~600 ℃） are the dehydration stage,and the third stage（600~900 ℃） is the decomposition stage.NiO was prepared from NiSO₄·6H₂O under the conditions as follows：calcination time was 30 min,calcination temperature was 850 ℃ and particle size was at 74~147 μm.