In routine clinical practice, the lack of scalable and cost-effective multiple blood biomarker assays has hampered the identification of individuals at high risk for Alzheimer's disease (AD). Here, we introduced an ultrasensitive antibody pair-based CRISPR protein detection (UACPD) platform that converts biomarker detection into CRISPRbased nucleic acid testing with a quantitative detection limit of 1 fM. This method combines CRISPR/Cas12a array device and antibody pair-based multi-recombinase polymerase amplification technology to specifically detect A beta 42 oligomers (A beta 42Os) and p-tau in plasma without any advanced equipment, thereby achieving early diagnosis of AD. Clinical validation revealed that UACPD with A beta 42Os and p-tau181 (or p-tau396,404) composite biomarkers as predictors had better diagnostic performance than single biomarker detection, with an area under the curve of over 0.94 and detection sensitivity, specificity, and accuracy exceeding 90.0 %. It is expected that UACPD will have broad application prospects in large-scale early screening of AD in the community.