The invention discloses a selective catalyctic reduction (SCR) denitration catalyst for high-sulfur flue gas and a preparation method thereof, relates to the field of SCR denitration catalysts, and specially, relates to the field of denitration of flue gas produced by a power plant utilizing high-sulfur coal as a raw material or a boiler utilizing heavy oil as a fuel. The SCR denitration catalystfor high-sulfur flue gas comprises 65 to 90 parts of titanium dioxide, 2 to 10 parts of tungsten trioxide, 0 to 7 parts of antimony lactate, 0.1 to 3 parts of selenium nitrate, 0.1 to 3 parts of vanadic anhydride, 2 to 6 parts of glass fibers, 1 to 3 parts of carboxymethyl cellulose, 2 to 7 parts of a rare earth oxide and 5 to 25 parts of a citric acid solution, wherein the citric acid solution has mass percent concentration of 48 to 52%. The preparation method comprises the following steps that the above raw materials are mixed well to form uniform plastic rubber; and the uniform plastic rubber is subjected to extrusion, drying and calcination to form the SCR denitration catalyst for high-sulfur flue gas. The SCR denitration catalyst for high-sulfur flue gas has active indexes which are similar to active indexes of a common catalyst, and a low SO2/SO3 transformation rate of 0.46 to 0.61%.