The invention relates to a preparation method for a titanium oxide modified microporous molecular sieve shape-selective catalyst. According to the method, titanium oxide is loaded to the outer surface of a microporous molecular sieve through a dipping method by taking the microporous molecular sieve ZSM-5 or MCM-22 as a matrix, taking tetrabutyl titanate as a titanium oxide precursor, and taking methylbenzene as a solvent; and the content of titanium oxide in the catalyst is 5-20% of the total weight of the catalyst. The obtained shape-selective catalyst has very good shape-selective catalysis performance for a process of synthesizing p-xylene by alkylation of methylbenzene and dimethyl carbonate.