[en] As a kind of high Tc superconductor application technique, a study on the development of energy storage fly wheel system using Y-Ba-Cu-O superconductor was performed. Quasi melt process was developed to fabricate the high magnetization superconductor which is needed to develop the fly wheel system and the effects of various process variables on the superconducting properties of the specimens were tested and analyzed. Magnetomechanical interactions between superconductor and permanent magnet was also experimented. A small prototype flywheel system in which the disc shape permanent magnet is rotated above the Y-Ba-Cu-O superconductor pellets was designed and test device for the prototype design was assembled to test its basic properties. (Author)