A series of solid superacid catalyst of SO₄^2-/WO₃-ZrO₂ containing different ratio of WO₃ and ZrO₂ have been prepared and characterized; regioselectivities of chlorobenzene mononitration with nitric acid, on these catalysts having different WO₃ content and calcination temperature, were investigated. Experiments show that chlorobenzene is nitrated with high para-selectivity at present of acetic anhydride using SO₄^2-/WO₃-ZrO₂ by a calcination step for 3 h at 600 ℃ as catalyst and a stoichiometric quantity of nitric acid. Nitration of chlorobenzene gives a 55.8% yield of mononitro compounds, and an ortho-para isomer ratio 0.30 in product distribution of chlorobenzene mononitration. The process is rapid, and represents an attractive method for green synthesis of nitroaromatic compounds.