Objective To understand the current situation of aspiration in ICU patients with different feeding patterns and to compare its characteristics,so as to provide a basis for targeted prevention of aspiration. Methods The study was a prospective study. The convenience sampling method was used to select patients who were admitted to the ICU of a tertiary hospital in Suzhou from January 2020 to April 2021 as the survey subjects. According to the different feeding patterns,patients were divided into an oral feeding group,a gastric tube feeding group and a post-pyloric feeding group. The occurrence and characteristics of dominant aspiration and micro-aspiration of patients with different feeding patterns were observed and compared. Results A total of 721 patients were enrolled. The incidences of dominant aspiration in the oral feeding group,the gastric tube feeding group and the post-pyloric feeding group were 8.10%,15.26%,and 11.26%. The incidences of micro-aspiration were 76.95%,77.11%,and 58.28%,respectively. The characteristics of the occurrence of dominant aspiration in 3 groups were compared. The time of first aspiration in the gastric feeding group earlier than that in the post-pyloric feeding group;the oral feeding group had the most frequent aspirations. The proportions of patients with impaired consciousness,gastric retention,intra-abdominal hypertension,dysphagia,and mechanical ventilation in the gastric feeding group and the post-pyloric feeding group were higher than that in the oral feeding group（Bonferroni method,all P<0.017）. The characteristics of micro-aspiration among 3 groups were compared;the proportion of patients with vomiting in the oral feeding group was higher than that in the post-pyloric feeding group;the acute physiology and chronic health scores and ICU stay time of the patients in the post-pyloric feeding group were higher than those in the oral feeding group;the proportions of patients with impaired consciousness and mechanical ventilation in the gastric tube feeding group and the post-pyloric feeding group were higher than that in the oral feeding group. The above differences are statistically significant（Bonferroni method,all P<0.017）. Conclusion The incidence of dominant aspiration and micro-aspiration in ICU patients fed by gastric tube was higher, and the characteristics of aspiration in ICU patients with different feeding patterns were significantly different. Clinically,individualized preventive measures should be taken as early as possible according to the characteristics of the patient and the way of eating.