The invention relates to a yield increase method of BTX aromatic hydrocarbons, and mainly solves a problem of low utilization values of heavy aromatic hydrocarbons and non-aromatic hydrocarbons in the prior art. The method comprises the following steps: sending a mixture containing many aromatic rings or polycyclic C6 and above heavy components from a reforming, catalytic cracking and gasoline hydrogenation apparatus and hydrogen to a fixed bed reactor containing a molecular sieve catalyst in order to obtain a reaction product rich in BTX, and adjusting the circulating load of the reaction liquid phase product and C9 and above fractions to adjust the BTX composition of a product. The added values of raw materials are improved, the technical problem is solved, and the method can be used in industrial production of aromatic hydrocarbons.