The invention belongs to the field of fine chemicals, and particularly relates to a preparation method of direct-chain perfluoro vinyl ether by using a sulfuryl fluoride group as an end group. The preparation method comprises the following steps of using the chlorinated alkyl vinyl ether as the raw material, performing the sulfonation reaction and chlorination reaction to obtain a product, and performing the addition reaction on the product with chloride gas, so as to obtain the chlorinated alkyl ether by using sulfuryl fluoride as the end group; performing the fluorination reaction on the chlorinated alkyl ether by using the sulfuryl fluoride as the end group, so as to obtain the perfluoro alkyl ether; performing the reduction reaction on the perfluoro alkyl ether, so as to obtain the direct-chain perfluoro vinyl ether by using the sulfuryl fluoride group as the end group, namely CF2=CFOCF2(CF2)nSO2F, wherein n is equal to 1 to 6. The preparation method has the advantages that by using the chlorinated alkyl vinyl ether as the raw material, the commercialized effect of the raw material is realized, the obtaining is easy, the cost is low and is lower than the cost of the fluoride-containing compound, the high-temperature cracking route and non-conventional monomer are avoided, the product is obtained via the high-yield reaction, the production of excessive fluoride-containing waste liquid is avoided, and the cost is reduced; the operation is simple and convenient, the implementing is easy, the yield rate is higher, the waste of the fluoride resource is avoided, and the production amount of the fluoride-containing waste is reduced.