This paper proposes new motion generation method by Interactive Evolutionary Computation based on Genetic Algorithm. This method generates new motions by combining some primitive motions, which are obtained by dividing already existing motions. This combining process is performed by IEC based on GA and then combined motions are generated according to the user preference. There is a problem that the variation of generated motions is very small if the number of already existing motions is too small. To compensate this problem, the authors also employ motion signal processing technique. Generated motions by combining primitive motions are modified through multi-level decomposition and composition of discrete wavelet-transform. When applying the composition process, each level wavelet coefficients are modified by their gain parameter which the user chooses through IEC and then motions modified by the user preference are generated. In this way, combinational use of IEC based on GA and motion signal processing technique allows the user to generate his/her required motions easily and intuitively.