The invention relates to a method for preparing an aromatic compound by catalyzing lignin to select depolymerization. The method comprises the following steps: taking an M(mpo)n complex (M=Fe, Co, n=3; M=Ni, n=2) as a catalyst, taking various beta-O-4 model molecules, organic lignin, lignosulfonate and alkali lignin as raw materials, and realizing high-selectivity catalytic cracking aryl-ether bands in a nitrogen atmosphere of 0.1 MPa at the temperature of 80 to 200 DEG C so as to obtain a phenolic compound. The conversion rate of the beta-O-4 model molecules reaches 100% at most, the productive rate of guaiacol reaches 95% at most, and the yield of styrene reaches 71% at most; when different lignins are used as raw materials for conversion, the yield of aromatic biological oil is 34% to 71%. The method has the characteristics of mild reaction conditions, no consumption of hydrogen source, high activity and selectivity, environment-friendly reaction process and the like.