Objective Investigate the clinical value of fecal calprotectin （FC）combined with blood indicators in the diagnosis and evaluation of the activity of ulcerative colitis（UC）. Methods 100 patients with UC diagnosed in Jiangsu Province Hospital from December 2017 to October 2020 were retrospectively analyzed， and 100 patients diagnosed with functional gastrointestinal disease in our hospital during the same period were selected as the control group，FC content was detected and compared between the two groups. According to the Ulcerative Colitis Endoscopic Severity Index（UCEIS），100 ulcerative colitis patients were divided into remission group，mild endoscopic activity group，moderate endoscopic activity group and severe endoscopic activity group， blood⁃related indicators（CRP，ESR，WBC，NLR，Hb，ALB）were detected respectively. FC and blood⁃related indicators of patients with different UC groups were compared. The ROC curve was drawn to analyze the diagnostic efficacy of FC combined with blood ⁃ related indicators to determine whether the UC endoscopy is active. Results The FC concentration of UC patients was significantly higher than that of the control group. The FC level of UC patients in the active phase was also higher than that of the control group（P < 0.05）. FC was combined with blood⁃ related indicators to make ROC curve，single FC had a high diagnostic value，and the evaluation value of FC com⁃ bined with blood indicators was better than FC single index. Conclusion FC is a good evaluation index to judge the disease activity of UC patients，and it can be used as an auxiliary index to evaluate the disease activity of UC patients.