The invention discloses a hydroxysulfobetaine surfactant and a preparation method and an application thereof, which belong to the field of an oil displacement agent. A chemical structural formula of the hydroxysulfobetaine surfactant is shown as a specification, wherein, n is an integer between 8 and 30, m is n-2, and x is 2 or 3. The hydroxysulfobetaine surfactant can reduce the oil-water interfacial tension to lower than 0.01 mN/m, the performance of the hydroxysulfobetaine surfactant is stable, and the hydroxysulfobetaine surfactant can be used as an oil displacement agent during a petroleum exploitation process, and can obviously increase the recovery efficiency of the crude oil.