β-Amyloid (Aβ) protein deposition, oxidative stress, and metal ion imbalance are established pathological features of Alzheimer's disease (AD), highlighting the imperative to efficiently reduce Aβ aggregates formation, alleviate oxidative stress, and chelate metal ions. Existing research indicates the necessity of developing multifunctional nanomaterials to facilitate multi-target therapy. In this work, we designed and prepared multifunctional selenium-doped carbonized polymer dots (SeCDs), and examined the multifunctionality at inhibiting Aβ, cleaning reactive oxygen species (ROS), and modulating copper ions. SeCDs exhibit efficient clearance of active hydroxyl radicals and superoxide anion radicals. In addition, SeCDs can chelate Cu ions, therefore reducing the cytotoxicity linked to the Aβ-Cu complex. More importantly, SeCDs can effectively reduce the level of intracellular reactive oxygen species. This study demonstrates the potential of carbon dots as a multifunctional β-sheet disruptor, while multifunctional SeCDs offer promising avenues for further research in the multi-target treatment of Alzheimer's disease. Meanwhile, this strategy provides a new perspective on the development of zero-dimensional carbon materials in Alzheimer's therapy.