Although the incidence of inflammatory bowel disease is stable in North American and European countries, the incidence of inflammatory bowel disease is increasing in newly industrialized countries, especially in China. The treatment drugs for ulcerative colitis include 5-aminosalicylic acid (5-ASA), glucocorticoids, immunosuppressants, and biological agents. The aim of this clinical trial is to evaluate the long-term safety and efficacy of sacral nerve stimulation in patients with ulcerative colitis