Abstract:Objective To explore the difference of gut microbiota between overweight/obese and normal weight people,and to provide reference for clinical prevention and treatment of overweight and obesity. Methods A total of 122 patients in Jilin People's Hospital from September 2018 to May 2020 were divided into overweight /obesity group (n=57) and normal body weight group (n=65) according to body mass index （BMI）. The content of gut microbiota and related blood biochemical indexes were detected in two groups. Results The levels of fasting blood glucose (Glu), TG, ALT, GGT, urea (Ur) and uric acid (UA) in overweight /obesity group were higher than those in normal weight group (P<0.01, P<0.05), while the level of HDL-C was lower than that in normal weight group (P<0.01). The content of Bacteriodetes and Prevotella in overweight/obese group were higher than those in normal weight group, however, the content of Firmicutes, Bifidobacteria, Lactobacillus, Enterococcus and Streptococcus were lower than those in normal weight group (P<0.01). The Bacteroides and Prevotella. were positively correlated with BMI (r=0.403, P<0.01; r=0.420, P<0.01), the Actinobacteria and Bifidobacteria were negatively correlated with BMI (r=-0.251, P<0.01; r=-0.436, P<0.01). Logistic regression analysis showed that Bifidobacteria, Lactobacillus, Enterococcus and Streptococcus were protective factors for weight loss after adjusting for age, gender, Glu, TG, HDL-C, ALT, GGT, Ur and UA (P<0.01). Conclusions The gut microbiota are difference between overweight/obese people and normal body weight people, Bifidobacteria, Lactobacillus, Enterococcus and Streptococcus are protective factors for weight loss. Improving gut microbiota may be a new strategy for the prevention and treatment of overweight and obesity.