Abstract: In recent years, the prevalence of overweight and obesity has increased drastically, and the mortality rate of related chronic metabolic disorders is much higher than other diseases. Many evidences suggest that the microbial community in the human intestine may play an important role in the pathogenesis of obesity. Oatβ-glucan has been proved to help lower cholesterol and reduce body weight. Besides, it can also change the composition and activity of the gut microbiota. The correlation between regulation of the intestinal flora and anti-obesity effect of oat β-glucan from the correlation between the gut microbiota and obesity, the anti-obesity effect as well as the prebiotic effects of oat β-glucan were discussed in this review.