The invention relates to a double-workpiece-platform same-phase rotation exchange method based on parallel mechanisms, and a device of the method, belonging to a technology of semiconductor manufacturing equipment. The device comprises two workpiece platforms, a rotary transfer platform and the two parallel anti-rotation mechanisms; in the rotating exchange process of the two workpiece platforms,the two workpiece platforms are caught and blocked by the rotary transfer platform which rotates around the center of a base station, so that the exchange between an exposure station and a pretreatment station can be realized; and the rotation of the two workpiece platforms can be controlled by the parallel anti-rotation mechanisms, so that the two workpiece platforms can be ensured to have the same phase in the exchange process. The invention solves the problems that the existing scheme for exchanging the platforms in a linear way is high in impact torque and more in platform exchange beats,the existing scheme for exchanging the platforms in a rotating way is reverse in phases of the two workpiece platforms, cables are wound, a target of a laser interferometer is lost, and the like; a smaller mass balance system is adopted, so that the balance time is better shortened, the system is simplified, the cost is reduced, the platform exchange beats are reduced, the time for exchanging theplatforms can be reduced, and the yield of a photoetching machine is effectively improved.