The invention relates to a ZnO-MnO2/gama-Al2O3 middle and low temperature coal gas fine desulfurizing agent and a preparation method thereof. The ZnO-MnO2/gama-Al2O3 middle and low temperature coal gas fine desulfurizing agent comprises the following active elements in percentage by mass: 15-20% of active element MnO2 and ZnO, and 80-85% of gamma-Al2O3; and the mole ratio of the MnO2 to the ZnO is 1:(7.5-8.5). The masses of precursor Zn(NO3)2*6H2O and Mn(NO3)2 required to prepare a solution are calculated by the mass percent and the mole ratio of the active elements, and the volume of the solution is approximately equal to the volume of the carrier gamma-Al2O3. The preparation method of the ZnO-MnO2/gama-Al2O3 middle and low temperature coal gas fine desulfurizing agent comprises the following steps of: adding the carrier gamma-Al2O3 to the solution for dipping at room temperature for 12h, putting a mixture to a 110 DEG C drying oven for drying, stirring once at each 3min during drying, transferring a sample to a Muffle furnace for roasting at 400-500 DEG C for 3h after water is totally evaporated so as to obtain the ZnO-MnO2/gamma-Al2O3 load-type desulfurizing agent. The desulfurizing agent prepared by the method disclosed by the invention is 150-170m<2>/g in specific surface area, 0.50-0.55cm<3>/g in pore volume and 10-14nm in average aperture, and has the characteristics of high middle and low temperature desulfurization precision and sulfur breakthrough volume, simple preparation process and the like.