The purpose of this protocol is to evaluate the efficacy and safety of HSK47388 as therapy in participants with moderately to severely active ulcerative colitis .

Inclusion Criteria:

1. Written informed consent must be obtained
2. Male or female, ≥18 years old and ≤75 years old
3. Willing and able to comply with study-specific procedures and the requirements of study protocol.
4. Diagnosis of ulcerative colitis (UC)
5. Baseline modified Mayo score of 5 to 9 and the endoscopy subscore 2 to 3
6. Demonstrated an inadequate response, loss of response, or failure to tolerate previous conventional therapy or advanced therapy.

Exclusion Criteria:

1. Subjects have used treatments within the time frame specified in protocol prior to the baseline visit
2. Diagnosis of indeterminate colitis, ischemic colitis, Crohn's colitis or clinical findings suggestive of Crohn's disease
3. Participants with current or prior diagnosis of fulminant colitis and/or toxic megacolon
4. Presence of a stoma
5. Presence or history of a fistula
6. Intra-abdominal or other major surgery performed within 12 weeks before baseline
7. History of extensive colonic resection
8. Subjects have laboratory values meeting the criteria in protocol
9. Concurrent conditions and history of other diseases as described in protocol