An apparatus for coding keys of graphic animation data and a method thereof are provided. The coding apparatus for encoding key data corresponding to time variables among graphic animation comprises a quantizer which quantizes the key data and generates quantized data; a differential pulse code modulation (DPCM) processing unit which DPCM processes the quantized data, receives the DPCM processed data, and by repeatedly performing DPCM processing, selects and outputs DPCM data having the lowest dispersion among N-th order DPCM data generated in the DPCM processing; a polar value removing unit which reduces the range of data by removing a polar value in the DPCM data output form the DPCM processing unit; and an entropy encoder which removes the redundancy of binary bits in the data output from the polar value removing unit and generates a compressed and encoded binary bit stream. In the method, by selecting a code where data dispersion is the lowest according to the characteristic of key data to be coded, redundancy of data to be coded increases such that coding efficiency increases. Also, by removing polar values appearing after DPCM, the coding efficiency increases.