The prevalence of obesity in the normal elderly was 10.3% (16/156), and there was no significant difference (p > 0.05) in age, education, fasting blood glucose, triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein, APOE E4, gender, smoker, drinker, tea drinker, physical exercise, hobby, scores of MoCA and GDS between the obesity group and the non-obesity group, what’ more, APOE E4 was not associated with fasting blood glucose, triglyceride, total cholesterol, high-density lipoprotein, low-density lipoprotein, diabetes, hypertension and hyperlipidemia (p > 0.05). Here, APOE is linked to obesity due to melanocortin 4 receptor deficiency.