The invention provides a method for preparing a catalyst for cracking heavy aromatics. The method comprises the following steps: mixing, drying and roasting pseudo-boehmite powder, zeolite molecular sieve powder, a peptizer and an extrusion aid to obtain a molded carrier; adding a set amount of water-soluble solvent with relatively polarity into a set amount of deionized water, and then adding at least one measured metal salt of Pt and Pd into the mixed solvent to prepare a steeping fluid; and adding the molded carrier into the steeping fluid, evaporating, and roasting the evaporated steeping product to obtain the catalyst for cracking heavy aromatics. The method has the advantages that the organic solvent with strong polarity is introduced and occupies a strong polarity site on the catalyst carrier, so that aggregation of noble metals on the catalyst carrier can be avoided, and the dispersity and hydrogenation activity of noble metals on the catalyst can be improved; and when ethylene cracked heavy aromatics are used as the raw material for light aromatic reaction, a high-activity noble metal catalyst can be used for quickly hydrogenating and saturating alkadiene substances, and thus occurrence of a polymerizing coke reaction can be avoided.