Background: Molecular markers associated with disease progression and prognosis of ulcerative colitis (UC) are still lacking in clinic. Aims: To investigate the expression and clinical significance of vanin 1 (VNN1) in intestinal mucosal tissue, serum and stool in patients with UC. Methods: A total of 100 UC patients and 100 healthy volunteers from Dec. 2018 to Jan. 2020 at the People's Hospital of Xinjiang Uygur Autonomous Region were recruited, and colonoscopy biopsy tissue samples, blood samples and stool samples were collected. PCR, Western blotting and immunohistochemistry were used to detect mRNA and protein expressions of VNN1 in intestinal mucosal tissue, respectively. The expression of VNN1 in serum and stool was determined by ELISA. Results: The mRNA and protein expressions of VNN1 in intestinal mucosal tissue in patients with UC were significantly higher than those in healthy controls (P<0.05). Immunohistochemistry results showed that VNN1 expression was significantly higher in intestinal mucosal tissue in patients with UC than in healthy controls (P<0.05). ELISA results showed that serum expression of VNN1 in patients with UC was significantly higher than that in healthy controls (P<0.05). There was no significant difference in expression of VNN1 in stool between patients with UC and healthy controls (P>0.05). Conclusions: The expressions of VNN1 in intestinal mucosal tissue and blood in UC patients are high, and can be used as a molecular marker of UC.