The present invention relates to a folding assembly of a table tennis table formed by a tabletop and inner and outer support stands, and mainly using a buckle mechanism to fold the tabletop and the inner and outer support stands in an upright position to facilitate the packaging, transportation, storage and moving of the table tennis table. The buckle mechanism includes a lever, two positioning covers, two buckle plates and two torsion springs, and the lever is provided for snapping a protruding pellet into a buckle notch of the buckle plate to achieve the effect of fixing and releasing the buckle between the tabletop and the outer support stand.