The invention relates to an assembly method for a spherical high-temperature phase-change thermal storage component. The assembly method comprises the following steps of providing phase-change material microspheres; providing a graphitized precursor; mixing and placing the phase-change material microspheres and the graphitized precursor in a quasi isostatic pressing silicon rubber die, pre-pressing with 50-100MPa to disperse the phase-change material microspheres in the graphitized precursor, and obtaining a pre-pressed ball blank; placing the pre-pressed ball blank in the quasi isostatic pressing silicon rubber die, pressing with 120-300MPa to enable a plurality of phase-change material microspheres to form a core and the graphitized precursor to form a substrate graphite layer encircling the core, and obtaining a finally-pressed ball blank; and carrying out thermal treatment on the finally-pressed ball blank to obtain the thermal storage component. The invention also provides the spherical high-temperature phase-changing thermal storage component. In the spherical high-temperature phase-change thermal storage component provided by the invention, the adopted graphite material is more resistant to high temperature and corrosion than that of metal, can be compatible and has favorable thermal cycle performance, and a component device for effectively packaging a high-temperature phase-change material is provided.