To investigate the current status and influencing factors of cognitive weakness in elderly patients with mild cognitive impairment (MCI). Methods: Convenience sampling was used to recruit 572 patients diagnosed as old-age MCI. The General Data Questionnaire, Montreal Cognitive Assessment Scale Beijing version (MoCA-B), FRAIL Scale, Activities of Daily Living Scale (ADL), Perceptive Social Support Scale (PSSS), and 30-item Geriatric Depression Scale (GDS-30) were used to investigate the general demographic data, cognitive function, lifestyle, and psychosocial status of elderly patients with MCI, and multiple Logistic regression analysis was used to study the influencing factors of it. Results: There was a high incidence of MCI in the elderly in China. The incidence was related to age, sex, heredity, lifestyle, and education level. The incidence rates of subsequent frailty and pre-frailty in elderly MCI patients were high. The incidence of frailty in elderly MCI patients was 13.64%, and the incidence of mild frailty was 28.67%. Logistic regression analysis showed that loneliness, depression, sleep disorders, and chronic diseases were risk factors for frailty in elderly patients with MCI (P<0.05), while higher education level, regular physical exercise, intellectual games, and social support were protective factors (P<0.05). Conclusion: The incidence rate of frailty in elderly patients with MCI is high, suggesting that medical staff should be attentive to frailty evaluation in addition to the comprehensive evaluation of elderly patients with MCI, and prevent and delay the occurrence and development of cognitive decline in elderly patients with MCI according to their risk factors.