In order to promote the development of flue gas denitrification technology in the steel industry, an impregnation method is used to prepare VPO-PEG-Cr/Ti catalysts, while their low-temperature denitrification activity and resistance of sulfur and water are tested. The activity test results show that when n(V)/n(P) (molar ratio) is 5, Cr mass fraction is 2%, the amount of active component load is 10%, the denitrification rate of the catalyst reaches more than 98% in the temperature range of 150 ~ 350 °C. When the reaction temperature is 200 °C and the flue gas contains 2 600 mg/m³ SO₂ and 8% H₂O, the denitrification efficiency of the catalyst is hardly decreased. Combined with the NH?-IR analysis, the addition of phosphoric acid and Cr increases the surface acidity of the catalyst and inhibits the adsorption and catalytic conversion of SO₂, PEG and TiO₂ increase the specific surface area of the VPO catalyst and the exposure of active sites. The FT-IR and TG results show that there is almost no sulfate deposition on the catalyst surface after the through-sulfur and through-water tests, and the catalyst shows good sulfur and water resistance.