The invention discloses a preparation method of a high-strength flue gas denitration catalyst. The preparation method comprises the following steps: taking titanium sulfate as the titanium source and critic acid as the complexing agent to prepare a TiO2-SiO2 composite carrier through an impregnation method, loading an active component and an auxiliary agent on the TiO2-SiO2 composite carrier so as to obtain denitration catalyst powder, mixing the denitration catalyst powder with glass fiber, wood slurry, polyacrylamide, carboxymethyl cellulose, ammonia water, and deionized water, and then subjecting the mixture to processes of kneading, aging, extruding, drying, and burning so as to obtain a honeycomb denitration catalyst. The preparation method has the advantages of simple preparation technology, low cost, and tight combination between TiO2 and SiO2 in the composite carrier. The prepared denitration catalyst has the advantages of good mechanical strength, wear-resistant property, and catalytic activity.