The invention relates to a catalyst and a method for improving the selectivity of preparation of aromatic hydrocarbon products from methanol in order to mainly solve the problem of low aromatic hydrocarbon yield caused by generation of a large amount of low carbon alkanes due to a hydrogen transfer reaction in the aromatization process. ZSM-5 molecular sieve is modified with different concentrations of Zn, Ag, Ni, Mo, Cu, Pt, Ga and other dehydrogenation metals, the modified ZSM-5 molecular sieve is processed to contain high valence oxide of V, Ce, Fe, La, Co, Au or Cr, the obtained ZSM-5 molecular sieve catalyzes efficient aromatization of methanol in weak oxidation gas and other inert diluted gas mixed reaction atmosphere, the partial pressure ratio of methanol is 0.1-10, the reaction temperature is 350-550DEG C, and the operating pressure is 0.1-4.0MPa. A catalyst is used to accelerate dehydrogenation aromatization of intermediate olefin substances, and the high valence metal oxide in the catalyst accelerates activation, and cooperates with weak oxidation gas to realize in situ elimination of hydrogen, so the alkane content in the product reaches the aromatic hydrocarbon selectivity improving purpose, and the aromatic hydrocarbon selectivity is higher than 72wt%.