Background: Alzheimer's disease (AD) is the most common type of dementia. International multilateral cost-of-illness (COI) studies have revealed that the cost of treating this disease is huge, which places a significant burden on patients' families and their healthcare systems. However, no such studies have been conducted in China. This study estimates the monetary costs of patients with AD in mainland China. Methods: This study planned to start in October 2015 and to finish in March 2016. It covered 30 provincial, municipal, and autonomous regions in mainland China. The sites and research centres in each region were selected randomly. The participating sites include Tier 3 hospitals, psychiatric hospitals, geriatric hospitals, nursing homes, and residences. More than 2500 patients with AD and their caregivers from all of the 81 research centres will be enrolled to fulfil the calculated sample size. The monetary costs of AD, which include direct medical costs, direct non-medical costs, and indirect costs, are being collected using the electronic medical record system and residence health system at each site; face-to-face interviews are being performed when necessary. Descriptive statistics will be used to summarise the patient characteristics and generalised linear models will be developed to calculate the costs. Results: The main findings will include national and per patient annual monetary costs of AD in China. Conclusions: To the best of our knowledge, this is the first large-scale cluster-randomized observational study to estimate the economic burden of AD in Chinese patients. The methodology used was based on China's current healthcare system and is suitable for the purpose of the study. Because the burden of AD on patients, families, healthcare providers, and society is substantial and increasing, it is important and necessary to understand the economic burden caused by this disease.