Dinitrotoluene(DNT) was prepared by nitrating toluene with nitric acid(97%) to avoid the use of mixed sulfuric acid/ nitric acid which is troublesome and energy-expensing for recycling. After investigating the factors affecting the nitration, the optimized conditions were worked out and might be as follows: molar ratio of nitric acid/ toluene 81, temperature 60 ℃, and time 1 h. The resulting DNT′s yield was 94%, purity was 98.8%, ratio of 2,4-DNT to 2,6-DNT was 4.3.