Objective: To investigate the preliminary screening results of Alzheimer's disease (AD) among the elderly in Ningbo City, Zhejiang Province and analyze the influencing factors, so as to provide insights into prevention and control of AD in the elderly. Methods: A multi-stage stratified proportional sampling method was used to select the registered residents aged 60 years and older in Ningbo City as subjects. Demographic characteristics, lifestyle factors, physical conditions and social activities of the subjects was evaluated with questionnaires. AD was screened using the Mini-Mental State Examination (MMSE), and factors affecting the positive rate of AD preliminary screening were identified using a multivariable logistic regression model. Results: A total of 34 027 elderly residents were investigated, with an mean age of (71.71±6.89) years. There were 15 115 males (44.42%) and 18 912 females (55.58%), 16 146 residents living in rural areas (47.45%) and 17 881 residents living in urban areas (52.55%). The positive rate of AD preliminary screening was 7.28% (2 476 cases). Multivariable logistic regression analysis showed that age (70 to 74 years, OR=1.357; 75 to 79 years, OR=1.807; 80 to 84 years, OR=2.782; 85 years and older, OR=4.907), gender (female, OR=1.118), residence (urban areas, OR=0.713), marital status (unmarried, OR=3.078; widowed/separated/divorced, OR=1.301), educational level (primary school, OR=0.629; junior high school and above, OR=0.609), occupation before retirement (others, OR=0.741), family genetic history (no, OR=0.651), household disposable monthly income (1 000 to 1 999 Yuan, OR=0.636; 2 000 to 2 999 Yuan, OR=0.569; 3 000 Yuan and above, OR=0.448), exercise (seldom, OR=0.855; regular, OR=0.780), number of chronic diseases (2~5, OR=1.328), hearing loss (no, OR=0.764), smell loss (no, OR=0.615), chronic constipation (no, OR=0.696), major negative life events (no, OR=0.804), subjective memory loss (no, OR=0.583), sleep quality (general, OR=0.640; good, OR=0.616), living style (living with spouse, OR=0.300; living alone, OR=0.315; living with children, OR=0.350) and social activities (2-3 times/week, OR=0.584; 4 times/week and more, OR=0.409) were factors affecting the positive rate of AD preliminary screening. Conclusions The positive rate of AD preliminary screening among the elderly in Ningbo City is relatively high. Age, gender, economic conditions, exercise, social activities and physical conditions were factors affecting the positive rate of AD preliminary screening.