This disclosure relates to a catalyst system adapted for transalkylation a C.sub.9+ aromatic feedstock with a C.sub.6-C.sub.7 aromatic feedstock, comprising: (a) a first catalyst comprising a first molecular sieve having a Constraint Index in the range of 3-12 and 0.01 to 5 wt. % of at least one source of a first metal element of Groups 6-10; and (b) a second catalyst comprising a second molecular sieve having a Constraint Index less than 3 and 0 to 5 wt. % of at least one source of a second metal element of Groups 6-10, wherein the weight ratio of the first catalyst over the second catalyst is in the range of 5:95 to 75:25 and wherein the first catalyst is located in front of the second catalyst when they are brought into contacting with the C.sub.9+ aromatic feedstock and the C.sub.6-C.sub.7 aromatic feedstock in the present of hydrogen.