Phosphomolybdic acid catalyst was prepared. Regioselectivities of nitration of toluene with nitric acid in the presence of phosphomolybdic acid catalyst prepared under different calcination temperatures were investigated. It was found that nitration of toluene without CCl₄ in the presence of a catalyst calcinated at 200 ℃ for 1.5 h gave a yield of 86.5% of mononitrotoluene with high para-selectivity,the ortho-para-isomer ratio being 1.33.