NOVELTY - Para-nitrotoluene is added to weak-polar or non-polar solvent and stirred. The para-nitrotoluene is heated under catalysis of reducing iron powder and iodine. The mixture is washed with sodium hydroxide dilute solution, after completion of reaction. Sodium hydrogen sulfite is added to 2,6-dichlone-4-nitrotoluene. The diazonium salt is added to hypophosphorous acid solution, and stirred. The mixture is delaminated, extracted, alkali washed, washed with water, decompressed and distilled to obtain 2,6-dichlorotoluene.    USE - Preparation of 2,6-dichlorotoluene used for preparing pyrethroid compound, preferably bifenthrin for killing insects and mites.    ADVANTAGE - The method enables safe and efficient preparation of 2,6-dichlorotoluene, without environmental pollution.    DETAILED DESCRIPTION - Para-nitrotoluene is added to weak-polar or non-polar solvent and stirred. The para-nitrotoluene is heated at 50-60 degrees C under catalysis of reducing iron powder and iodine. The chlorine is slowly filled at 60-90 degrees C. The mixture is washed with sodium hydroxide dilute solution, after completion of reaction. After washing with water to pH of 7, the mixture is cooled to 0-10 degrees C and processed to obtain coarse product of 2,6-dichlone-4-nitrotoluene. The coarse product of 2,6-dichlone-4-nitrotoluene is recrystallized with ethanol to obtain 2,6-dichlone-4-nitrotoluene. Sodium hydrogen sulfite, sodium hydrosulfite, sodium sulfide or hydrazine hydrate is added to 2,6-dichlone-4-nitrotoluene, and water is added and stirred. The reaction mixture is heated for 4-6 hours, cooled, filtered and dried to obtain 3,5-dichlone-4-nitrotoluene. Hydrochloric acid (30-40%) is added to 3,5-dichlone-4-nitrotoluene, mixed and cooled to -5 degrees C to 10 degrees C. Sodium nitrite solution is dripped at 10 degrees C, continuously stirred at 10-30 degrees C and reacted. Aqueous urea solution is added and stirred, after completion of reaction. The undissolved substance is filtered to obtain diazonium salt solution. The mass ratio of 3,5-dichlone-4-nitrotoluene and sodium nitrite is 1:0.8-1.2. The diazonium salt is added to hypophosphorous acid solution cooled by ice water bath, and stirred at 10-30 degrees C for 8-10 hours. The mixture is delaminated, extracted, alkali washed, washed with water, decompressed and distilled to obtain 2,6-dichlorotoluene.