Ulcerative colitis(UC) is characterized by the impaired intestinal barrier，with the clinical manifestations including persistent inflammation，ulceration of the rectal mucosa，and recurrent inflammatory bowel disease.The spleen is closely related to the intestinal barrier，and the dysfunction of the spleen being in charge of the defensive function is the main pathogenesis of UC.However，the microscopic mechanism of this pathogenesis remains unclear.The intestinal barrier is similar to the spleen being in charge of the defensive function.The impairment of the intestinal barrier is mutually causal with UC.The TCM theory of spleen being in charge of the defensive function can be explained from the perspective of intestinal barrier.The modern medical therapy for UC remains to be developed，and drug therapies have limitations such as side effects and aggravation after drug withdrawal.The TCM treatment method of replenishing qi and invigorating spleen based on the TCM theory of spleen being in charge of the defensive function can restore the intestinal barrier and promote mucosal healing without inducing side effects，which has a significant clinical value for promoting the healing and preventing the recurrence of UC.