The invention relates to a gemini surface activity initiator and a preparation method thereof. An amphiphilic compound containing polyhydroxyl amine and dioctyl groups is firstly synthesized, the compound has the high characteristics of emulsifying oily monomers, hydrophilic tertiary amine can generate a redox reaction with potassium persulfate at room temperature, cation free radicals are firstly formed on nitrogen atoms and then converted into carbon free radicals at the adjacent positions, generation of the free radicals can be repeated for multiple times and flexibly controlled, a serially-initiated multiphase concatenating polymerization mode is achieved, polymerization of styrene and vinyl acetate and polymerization of styrene and acrylamide are initiated on a water-oil interface in sequence, and then a segmented copolymer is obtained. Experiments prove that the feed ratio of monomers is quite consistent with the component ratio of the copolymer, that is to say, the initiation efficiency of the initiator is very high, this mode of polymerization reaction is mild and controllable in condition and low in energy consumption, no other organic solvent or emulsifier is used, the product is pure, and the requirements of green chemistry are totally met.