The invention discloses a synthetic technology of vulcanizing isobutene with one-step method in the sulfide technique field of acyclic unsaturated carbon skeleton, which comprises the following steps: adding the elemental sulfur and accelerant in autoclave; heating to 150-250Deg. C; mixing for 0.5 hours; adding isobutene in the autoclave slowly; increasing the pressure to 2-10MPa for 1-8 hours; cooling less than 80Deg. C; extruding the mixture from the high-pressure autoclave with the rest pressure; separating the organic phase after stewing and layering; distilling; filtering; getting the vulcanized isobutene product( the accelerant is inorganic weak base material). The invention is provided the high efficient, the low cost and the clean reaction, which solves the prior technique problem.