The invention relates to a fixed-rotation-center external fixator for ankle-foot malformation correction. The fixed-rotation-center external fixator comprises a near-end ring, a far-end ring, two telescopic branch chains, one fixed-point rotary branch chain, an annular guide rail and a kirschnner wire assembly. Kirschnner wires rigidly fix the near-end ring and the far-end ring with the tibia andthe foot respectively, the two telescopic branch chains are fixed to the front sides of the rings, the fixed-point rotary branch chain is fixed to the rear sides of the rings and connects the near-endring and the far-end ring, and the annular guide rail is arranged at the near-end ring; by adjusting a slide block of the annular guide rail and movable pairs on the branch chains, the far-end ring can achieve spatial six-degree-of-freedom movement, the rotation center of the far-end ring points to the rotation center of the ankle joint all the time, and any spatial three-dimensional ankle-foot malformation can be corrected. According to the fixed-rotation-center external fixator, the design of the three branch chains is adopted, a 2-PUPS / PUPRRR parallel structure is formed, the fixator has six degrees of freedom, it can be achieved that the rotation center coincides with the ankle joint all the time, requirements of different patients can be met, and the fixed-rotation-center external fixator has the advantages that the structure is simple, the number of the movement branch chains is small, the working space is large, and interference is not easily caused.