The invention belongs to the technical field of catalysis, and relates to a monolithic catalyst for preparation of dimethyl ether from synthetic gas and a preparation method thereof. The preparation method comprises the following steps: immersing honeycomb ceramics in an aluminum nitrate/urea mixed water solution in a high-pressure kettle to be subjected to treatment to obtain a support precursor, and performing heat treatment on the support precursor to obtain a support; immersing the upper section part of the obtained support in a copper nitrate/zinc nitrate/aluminum nitrate mixed solution, then immersing the upper section part in a precipitant solution, performing washing to obtain a catalyst precursor 1, and performing heat treatment on the catalyst precursor 1 to obtain a catalyst semifinished product; and immersing the lower section part of the catalyst semifinished product in a sulfuric acid solution to be subjected to treatment, then performing washing to obtain a catalyst precursor 2, and performing heat treatment on the catalyst precursor 2 to obtain the monolithic catalyst. The catalyst prepared by the method has high CO conversion rate and high dimethyl ether selectivity.