This cross-sectional study assessed the knowledge level of Alzheimer’s disease (AD) among 143 community-dwelling elderly individuals in Shanghai, China, using a stratified cluster sampling method. The overall AD knowledge score was 55.82 ± 9.79 (out of 66), with the highest score in caregiving knowledge (21.72 ± 2.67), followed by preventive knowledge (18.16 ± 3.92), and the lowest in disease-specific knowledge (15.94 ± 4.86). Multivariate linear regression identified five key factors significantly associated with the total knowledge score: absence of a family history of depression (β = -18.216, P < 0.001), living with a spouse (β = -1.429, P = 0.013), higher personal monthly income (β = 1.851, P = 0.007), actively seeking dementia-related information (β = -4.137, P = 0.005), and not having sought medical consultation for suspected cognitive impairment (β = 3.701, P = 0.034). The model explained 27.7% of the variance (R² = 0.277, F = 10.485, P < 0.001). These findings revealed a moderate level of AD knowledge with significant disparities across domains and population subgroups. The results underscore the need for targeted health education strategies, particularly for individuals living alone, those with lower socioeconomic status, and those with a family history of mental health conditions, to enhance AD awareness and mitigate its impact within China’s aging population.