A method and an apparatus for encoding and decoding a position interpolator including key data and key value data are provided. The method for encoding a position interpolator includes (b) generating key data and key value data to be encoded by extracting, from a first animation path constituted by the position interpolator, a minimum number of break points, which can bring about an error of no greater than a predetermined allowable error limit between the first animation path and a second animation to be generated by the extracted break points, (d) encoding the key data generated in step (b), and (e) encoding the key value data generated in step (b).