The invention discloses a heavy aromatics transalkylation catalyst. The catalyst comprises a carrier and metallic elements M1 and M2 supported on the carrier, wherein the metallic element M1 is one or more elements of Ru, Rh, Pd, Ag, Os, Ir, Re, Pt and Au; and the metallic element M2 is one or more elements of lanthanide series. The carrier is prepared by the following steps: a NaY molecular sieve is contacted with organic acid in an aqueous solvent so as to obtain a modified NaY molecular sieve, wherein the pore opening of the modified NaY molecule sieve is trumpet-shaped. According to the heavy aromatics transalkylation catalyst, anti-carbon formation capability is raised, and probability of blocking the molecular sieve's pores is reduced. Then, activity of the catalyst is raised, and service life of the catalyst is prolonged. Therefore, the heavy aromatics transalkylation catalyst has a good industrial application prospect.