The invention relates to a preparation method for a pin diode string equipped with a table-shaped active region and used for a sleeve antenna. The preparation method comprises the steps of (a), selecting an SOI substrate; (b), etching the SOI substrate to form the table-shaped active region; (c), performing P type Si material and N type Si material deposition on the periphery of the table-shaped active region by adopting an in-situ doping process to form a P region and an N region respectively; (d), depositing a polycrystal Si material on the periphery of the table-shaped active region; and (e), manufacturing lead photoetching PAD on the surface of the polycrystal Si material to form the pin diode string. According to the embodiments, the high-performance pin diode string, equipped with the table-shaped active region and applicable to formation of the reconfigurable annular antenna, can be prepared and provided by adopting the in-situ doping process.