Objective To explore the relationship between the drug resistance status and metabolic phenotype of Clostridium difficile (CD)in ulcerative colitis (UC). Methods A total of 286 UC patients admitted to our hospital from July 2018 to July 2021 were selected as the study objects. The patients were divided into CDI group (100 cases) and non-CDI group (186 cases) according to whether Clostridium difficile infection (CDI) was present. The clinical data, laboratory indexes, endoscopic manifestations and drug use of the two groups were compared and analyzed. Toxin genes and ribosome typing were detected. The sensitivity of CD to different antimicrobial agents and its relationship with the type were analyzed. Multivariate Logistic regression analysis was performed to analyze the independent risk factors of UC combined with CDI. The prediction model of nomogram was established and evaluated. Results There were 100 strains of toxin-producing bacteria, including 57 strains of TcdA+TcdB+ type and 43 strains of TcdA-TcdB+ type. There were 23 types of ribosomes, including RT012 (16 strains, 16.00%), RT001 (13 strains), HB024 (11 strains), RT017 (8 strains) and HB025 (7 strains). The resistance rates of CD to ciprofloxacin (CIP), clindamycin (CC), erythromycin (E) and tetracycline (TE) were all high. The resistance rates of CD to rifaximin (RFX), levofloxacin (LVX), ceftriaxone (CRO), tigecycline (TGC), rifampin (RA) and chloramphenicol (C) were all low. All types of CD were sensitive to meropenem (MEM), metronidazole (MTZ), vancomycin (VA) and fidaxomicin (FDX), and the multidrug resistance rate was as high as 68.00%. Compared with other types, RT017 was more resistant to CRO, E, TE, LVX, RA and RFX (P<0.05), and RT001 was more resistant to TGC (P<0.05). The multidrug resistance rate of CD in HB024 and all other types (except the 5 main types) is relatively low, and the multidrug resistance rate of CD in RT012, RT001, RT017 and HB025 is more than 80% (P<0.05). Age≥65 years, history of surgery, severe UC, endoscopic examination with pseudomembrane, systemic glucocorticoid use, and use of IFX were all independent risk factors for UC complicated with CDI (P<0.05). The results of the nomogram prediction model showed that each risk factor totaled 374 points. The evaluation results of receiver operating characteristic curve (ROC), calibration curve and decision curve analysis (DCA) showed that the prediction model had high discrimination, accuracy and validity.Conclusion CD has high resistance to CIP, CC, E and TE, which should be paid attention to. It is highly sensitive to FDX, MTZ and VA. Age≥65 years old, history of surgery, severe UC, pseudomembrane on endoscopy, systemic glucocorticoid use, and use of IFX were all independent risk factors for UC complicated with CDI