The present invention provides a weight-adjustable dumbbell component. The weight-adjustable dumbbell component includes a dumbbell base, dumbbell plates, and a dumbbell bar assembly; two ends of the dumbbell base are provided with abutting bumps fitted with inserting holes, limiting mechanisms are unlocked when the abutting bumps extend into the inserting holes, the limiting mechanisms are locked when the abutting bumps are separated from the inserting holes, and the limiting mechanisms are used for limiting relative rotation of a rotating shaft. The dumbbell plates are prevented from loosening during use, parts for unlocking the limiting mechanisms are arranged on the dumbbell base, thus the danger that the limiting mechanisms are unlocked due to improper use is effectively avoided.