Abstract: OBJECTIVE To analyze the infection situation and risk factors for Clostridium difficile infection（CDI） in patients in intensive care unit（ICU）. METHODS A total of 118 critically ill patients who were admitted to ICU of Jinzhou Central Hospital from Jun 2018 to Jul 2020 were enrolled. Non-repetitive fresh stool specimens were collected from patients to be used for selective anaerobic culture and toxin gene test. The typing of toxin gene-positive strains was conducted by multilocus sequence typing（MLST）. According to the presence or absence of CDI, they were divided into the CDI group and non-CDI group. The clinical characteristics and laboratory test results between the two groups were compared; the risk factors for CDI were analyzed, and laboratory indexes and prognosis during hospitalization in ICU were compared. RESULTS Among the 118 specimens, 21 strains of C. difficile were isolated, with the incidence rate of 17.80%（21/118）. The polymerase chain reaction（PCR） test showed that there were 18 strains of A⁺B⁺ type and 3 strains of A^-B⁺ type, and no A^-B^- type genotype or binary toxin gene（ctdA/ctdB） were detected. MLST results showed that the ST types in the 21 strains of C. difficile were mainly ST2, ST3 and ST35, accounting for 19.06%, 14.29% and 14.29%, respectively. Multivariate analysis showed that age older than 55 years old, stay time in ICU longer than 8 d, APACHE II score, mechanical ventilation, antibiotic usage time longer than 5 d, usage of stool specimens were collected from patients t（PPI） were independent risk factors for CDI in severely ill patients in ICU（P＜0.05）. The length of hospitalization stay in the CDI group was significantly longer than that in the non-CDI group; levels of C-reactive protein（CRP）, erythrocyte sedimentation rate（ESR） and procalcitonin（PCT） during hospitalization in ICU were significantly higher than those in the non-CDI group; level of albumin（ALB） was significantly lower than that in the non-CDI group（P＜0.05）. CONCLUSION There may be higher CDI risk in severely ill patients in ICU. CDI is of certain molecular epidemiological characteristics, which may effect on the prognosis. Special attention should be paid on patients, who were with elderly age, long-term hospitalization in ICU, critically ill, long mechanical ventilation and antibiotic usage time, usage of β-lactam antibiotics and PPI, and C. difficile detection should be carried out in them.