The invention discloses a preparation method of a gamma-Al2O3@SAPO-34 core-shell structure catalyst. The preparation method comprises the following steps: preparing an SAPO-34 precursor solution; adding gamma-Al2O3 powder to the SAPO-34 precursor solution prepared in the step (1) according to the core-shell mass ratio of gamma-Al2O3:SAPO-34 of (1:2)-(2:1), performing uniform stirring continuously,and then, transferring the product into a reactor; and performing hydrothermal crystallization for 48h at 200 DEG C, performing cooling and filtration, performing washing to neutrality with deionizedwater, performing drying for 6h at 105 DEG C, and performing roasting for 3h at 500-600 DEG C to obtain the catalyst. The catalyst prepared by the preparation method disclosed by the invention can simultaneously improve the conversion rate of methanol and the selectivity of low-carbon olefin and has long service life.