The invention relates to fulvestrant and preparation of an intermediate and comprises a method for preparing fulvestrant from new isothiourea sulfonate. The route is short, the operation is simple, raw materials are easy to obtain, the condition is mild, the overall reaction time is greatly shortened, the production cost is reduced, the total yield is high, no protective group is introduced into hydroxyl in 3 and 17 positions, and the method is suitable for large-scale industrial production.