Inclusion Criteria:
* The subject or guardian must provide voluntary informed consent;
* Diagnosis based on the "Chinese Guidelines for the Diagnosis and Treatment of Ulcerative Colitis (2023, Xi'an)": Patients diagnosed with UC (based on comprehensive evaluation including clinical, imaging, pathological, and endoscopic assessments), with a follow-up period of more than 3 months;
* Moderate to severe active ulcerative colitis: Patients meeting the criteria of a clinical modified Mayo score of 6-12 points and an endoscopic Mayo score (ES) ≥ 2 points (within 10 days prior to baseline);
* Previous treatments with all domestically approved medications for UC, including conventional immunosuppressive drugs, biologics, and small molecule drugs, have failed;
* Hematological, liver and kidney function, cardiopulmonary function, and coagulation function meet specific criteria.
Exclusion Criteria:
* Women who are pregnant or lactating;
* Any condition that, in the judgment of the Investigator, could increase the subject's risk or compromise the interpretation of the trial results;
* Diagnosed with CD (Crohn's Disease) or indeterminate colitis (IBD-unclassified), or other types of colitis or enteritis that may confound efficacy assessment;
* Currently diagnosed with fulminant colitis and/or toxic megacolon;
* UC limited to the rectum;
* Currently or likely to require colostomy or ileostomy;
* Has previously undergone total proctocolectomy or partial colectomy.
* Patients who test positive for hepatitis B surface antigen (HBsAg) should be excluded; if HBsAg is negative but hepatitis B core antibody (HBcAb) is positive, and peripheral blood HBV DNA is above the detection limit, they should be excluded; patients who test positive for hepatitis C virus (HCV) antibodies and HCV RNA should be excluded; patients who test positive for human immunodeficiency virus (HIV) antibodies; patients who test positive for cytomegalovirus (CMV) DNA; patients who test positive for Epstein-Barr virus (EBV) DNA; patients who test positive for both treponemal-specific antibodies and non-specific antibodies for syphilis should be excluded.
* Any uncontrolled active infection present at the time of signing the ICF.
* Subjects who have had severe, opportunistic, or chronic/recurrent extra-intestinal infections within 2 months prior to screening; evidence of active/infectious herpes zoster infection within 8 weeks prior to screening; active tuberculosis or latent tuberculosis infection present at screening.
