This study aimed to elucidate whether malnutrition is associated with cognitive impairment in an older Chinese population. A cross-sectional study was conducted in 2365 participants aged 60 years or older from January 2013 to September 2019. Nutritional status was measured by using the Mini Nutritional Assessment Short Form (MNA-SF). Cognitive function was assessed with the Mini-Mental State Examination (MMSE). The relationship between malnutrition or each Mini Nutritional Assessment Short Form domain and cognitive impairment was examined with univariate and multivariate logistic regression analysis. The prevalence of malnutrition, risk of malnutrition, and cognitive impairment was 5.54%, 33.45%, and 36.74%, respectively. The prevalence was higher in those 80 years and older: 7.88%, 40.75%, and 53.65%, respectively. The Mini-Mental State Examination score was positively correlated with the Mini Nutritional Assessment Short Form score (r = 0.364, P < 0.001). After adjustment for age, gender, education, marital status, and living alone, malnutrition (odds ratio (OR) = 3.927, 95% confidence interval (CI): 2.650-5.819), anorexia (OR = 1.454, 95%CI: 1.192-1.774), weight loss (OR = 1.697, 95%CI: 1.406-2.047), impaired mobility (OR = 4.156, 95%CI: 3.311-5.218), and psychological stress (OR = 1.414, 95%CI: 1.070-1.869) were significantly associated with an increased risk of cognitive impairment. Our results suggest that the prevalence of malnutrition and cognitive impairment is relatively high and increases with age. Malnutrition, anorexia, weight loss, impaired mobility, and psychological stress are significantly associated with an increased risk of cognitive impairment. Therefore, clinicians should assess the nutritional and cognitive status of the elderly regularly to improve early detection and timely intervention.