Background: Population aging increases the economic burden of Alzheimer's disease (AD). Early screening for mild cognitive impairment (MCI) has the potential to mitigate this burden, but optimal strategies regarding screening coverage and age targeting remain unclear. Objective: To explore the impact of varying MCI screening coverage and age-specific screening strategies on the AD population size and the associated healthcare costs in Shanghai, using a system dynamics approach. Methods: A system dynamics model was developed to evaluate disease population and economic costs associated with MCI and AD at different coverage levels and age groups. A cost-benefit comparison was conducted to identify the screening coverage rate and age threshold that maximize cost-effectiveness, balancing reductions in AD-related costs against increases in screening expenditures. Results: Increasing MCI screening coverage significantly reduced economic costs across the AD spectrum but also increased overall screening expenditures. Expanding screening to additional age groups produced similar effects. Cost-benefit analysis identified an optimal strategy: initiating screening at age 60 or 65 with 80% coverage, which achieves substantial cost savings while avoiding the diminishing returns and excessive expenditures associated with broader, less targeted screening approaches. Conclusions: Strategically designed MCI screening can reduce the economic burden of AD, improve public health outcomes, and promote social well-being. To maximize societal benefit, screening scope must be balanced with cost. Policymakers and healthcare professionals should tailor strategies to local contexts and urgently adopt innovative technologies such as digital health and artificial intelligence-based solutions, to enhance accessibility and scalability of MCI screening strategy.