Alzheimer's disease (AD) is a progressive and irreversible neurodegenerative disorder, the treatment of which remains a major clinical challenge. In recent years, significant progress has been made in the immunotherapy of AD. Notably, monoclonal antibodies targeting amyloid-β (Aβ) have already been applied in clinical practice. However, as macromolecular therapeutics, antibodies face substantial challenges in crossing the blood-brain barrier (BBB) efficiently. Systemic administration typically requires high dosages to achieve the therapeutic level of brain exposure, which may trigger adverse events such as amyloid-related imaging abnormalities (ARIA) and thus restrict their widespread clinical application. To resolve this problem, various engineering strategies for modifying anti-Aβ antibodies have been developed. This review summarizes four major modification categories: BBB-penetrating bispecific antibodies (BsAbs), glycosylation engineering, antibody-drug conjugates (ADCs), and chimeric antigen receptor (CAR)-based cell therapies (including CAR-macrophages, CAR-T cells, and CAR-astrocytes). We provide an in-depth discussion of their delivery efficiency, targeting capability, and safety, aiming to lay a foundation for developing safer and more effective next-generation anti-Aβ antibody therapeutic strategies.