The residual carbon and carbides were typical phenomenon in the ceramic powder synthesis by a chemical way. The carbon removal process is commonly used, but there were few articles referred to the structure and morphology of residual carbon. In this paper, a precursor salt system with high urea content was adopted to prepare AlN powder by calcination in a nitrogen protective atmosphere. The structure and morphology of the products obtained by calcination in the temperature range from 850 ℃ to 1 500 ℃ were characterized by X-ray diffraction, infrared and Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy. Meanwhile, the changes in the structure and morphology of carbon-containing products during the synthesis of AlN, and the interdependent growth relationship between AlN and carbon-containing products were analyzed. The results show that the graphitization transformation of amorphous carbon is accompanied by the growth of AlN, and the morphology of AlN particles is also affected by the morphology of carbon-containing residual products.