This study will be divided into two parts: development of the mobile medical application for older adults with subjective memory decline and the intervention application. Start by developing and optimizing the application based on the rapid prototyping model. Then, in accordance with the framework of designing and evaluating complex intervention measures proposed by the Medical Research Council of the United Kingdom, pre-experiments will be carried out to apply the developed application to the actual intervention process to test the intervention effect, feasibility, and other contents of the application.

Inclusion Criteria:

• Patients with subjective memory complaints by SMCQ for 6 months and above.
• Individuals age over 60 years (depending on the characteristics of the disease, it can be relaxed to 55 years) are included.
• Older adults owning and being able to use smartphones to access the Internet, or whose caregivers can assist in the completion can also be included.
• Older adults who voluntary participate in the study and provide informed consent are also included.

Exclusion Criteria:

• Older adults diagnosed with cognitive or mild cognitive impairment.
• Older adults diagnosed with other neurological disorders ( cerebrovascular disease, encephalitis, brain tumor, brain trauma, epilepsy, Parkinson 's disease, depression, mania, etc. ), metabolic diseases ( anemia, thyroid dysfunction, folic acid and vitamin B12 deficiency, etc. ), carbon monoxide poisoning and cognitive decline caused by general anesthesia
• Older adults with serious medical and surgical diseases who cannot complete the experiment are also excluded.