The keggin-type H6PMo9V3O40 on silica gel had be prepared and worked very efficiently with high para selectivity for the mononitration of methyl salicylate with nitric acid using carbon tetrachloride as solvent. The effects of various parameters such as time of reaction, temperature, weight of catalyst and nitric acid had been studied. The yield of methyl mononitrosalicylate was up to 94% with p/o 6.58. The catalyst could be recovered easily and reused for fived times with high catalytic activity.