Catalytic activity of silicotungstic acid for nitration of toluene was studied． Effects of some factors， including dosage of catalyst， calcination temperature of catalyst， nitrated reaction time and recovered catalyst, on the selectivity of toluene in mononitration at the presence of silicotungstic acid catalyst were studied by gas chromatography (GC)． The results show high selectivity when the temperature is controlled at 50 ℃， and the nitrated reaction time is 90 min， toluene is nitrated by using 95% nitric acid as nitrating reagent at the presence of acetic anhydride， 1.0 g silicotungstic acid catalyst is calcinated at 300 ℃ for 1.5 h. The o/p (ratio of ortho to paro isomer of toluene nitration) ratio is 0.89 in product distribution of toluene nitration， lower than 1.67 using sulfonitric acid as catalyst. The yield of products is 91.6%． The catalyst can be reutilized up to five times with little decrease in activity．