Constipation is one of the most common gastrointestinal (GI) disorders in clinical practice, with approximately 11-20% of adults worldwide suffering from constipation. Clinically, the frequency of defecation is reduced, or the defecation is laborious, obstructed, difficult, and the stool is dry and difficult to solve, which is called constipation. Clinically, constipation is difficult to treat and over-reliance on laxatives often leads to water and electrolyte imbalance, gastrointestinal dysfunction, melanosis of the colon, relaxation of anal sphincter and other problems, and even leads to colorectal cancer, diabetes, anorexia nervosa and other complications in some cases. Therefore, it is very important to find a safe and effective laxative drug or diet to improve and relieve constipation symptoms. The health promotion effect of resistant starch is mainly due to the short-chain fat and gas produced by microbial fermentation in the colon, and its role in preventing colorectal cancer and some diet-related chronic diseases is stronger than dietary fiber, and it can effectively overcome the adverse odor, rough texture, poor quality and other drawbacks of food fortified with dietary fiber. Ruminococcus bromii is a specific microorganism that degrades resistant starch. The starch decomposing enzyme of R. bromii has a unique tissue structure and forms a multi-enzyme complex. Through the adhesion protein and dockerin module, it is attached to the cell surface through the scaffold protein in the cellulose body. Big data analysis showed that the relative abundance of R. bromii in healthy people was significantly higher than that in patients with constipation. Therefore, the purpose of this clinical trial is to supplement resistant starch to patients with constipation: (1) Observe whether the symptoms of patients with constipation have improved; (2) Analyze the changes of intestinal microorganisms in patients with constipation; and (3) Verify whether the relative abundance of R. bromii is increased and analyze the correlation between the relative abundance of R. bromii in intestine and the improvement of constipation symptoms in patients with constipation.