Ulcerative colitis (UC) is a chronic inflammatory disease of the intestine that presents clinically with abdominal pain, mucopurulent stools, and posterior urgency. The lesions of UC are mainly concentrated in the rectal and colonic mucosa and submucosa. For patients with mild to moderate UC, the best pharmacological treatment includes glucocorticoids, immunosuppressants, antibiotics, and biologics, but the long-term application can have serious toxic side effects. Currently, nearly 40% of UC patients are treated with herbal natural products in combination with traditional medications to reduce the incidence of toxic side effects. Flavonoid herbal natural products are the most widely distributed polyphenols in plants and fruits, which have certain antioxidant and anti-inflammatory activities. Flavonoid herbal natural products have achieved remarkable efficacy in the treatment of UC. The pharmacological mechanisms are related to anti-inflammation, promotion of mucosal healing, maintenance of intestinal immune homeostasis, and regulation of intestinal flora. In this paper, we summarize the flavonoid components of anti-ulcerative colitis and their mechanisms reported in the past 10 years, to provide a basis for rational clinical use and the development of new anti-ulcerative colitis drugs.