In the 500mL there-necked flask, add chlorsulfonic acid 233 grams (2.0mol), slowly add chlorobenzene 112.5 grams (1.0mol) under stirring, finish, be warming up to 80-90 ℃, insulation reaction 4 hours is chilled to 50 ℃ then, drips phosphorus trichloride 137.5 grams (1.0mol), drip to finish and be warming up to 80-90 ℃, insulation reaction 4 hours is chilled to below 15 ℃, is diluted in the frozen water, filter, get SULPHURYL CHLORIDE filter cake 263.8 grams, content 78.2%, yield 97.3%.