The invention relates to a method for preparing an aromatic compound by direct catalytic cracking of lignin. Under the combined action of a catalyst and a solvent, industrial lignins such as natural lignin, sodium lignin sulfonate, alkali lignin and dealkalized lignin are used as raw materials and are selectively cracked into the aromatic compound derived from C6-C9 phenolic group, guaiacol groupor syringyl through the catalytic process. The conversion rate of the raw materials reaches over 50%, and the guaiacol group and the syringyl aromatic compound account for over 90% in a cracking product. The method has the characteristics of cheap raw materials, high conversion rate, high yield of the aromatic compound and mild reaction condition.