Objective To explore the variation trend of gastric residual volume and influencing factors of full feeding in ICU patients receiving continuous enteral nutrition. Methods Patients admitted in medical ICU of Peking Union Medical College Hospital from January 2014 to August 2019 were enrolled,and a retrospective analysis of patients receiving continuous enteral feeding via nasogastric tube was performed. The variation trend of gastric residual volume during the first 7 ICU days was analyzed;the full feeding rates of the 7th day between different groups with gastric residual volume more or less than 200 ml were compared;influencing factors of full feeding were evaluated by univariate analysis and multivariate logistic regression analysis. Results 1 057 ICU patients were enrolled,and the peak of gastric residual volume during the first 7 ICU days occurred at the 8th to 12th hour after the beginning of continuous enteral feeding. 715 patients who stayed in ICU over 7 days were analyzed for full feeding;23.1% of patients reached full feeding target on the 7th day;the full feeding rates of patients with gastric residual volume larger than 200ml(14.1%) were significantly lower than those of patients with less gastric residual volume(24.3%, χ2=4.023,P=0.045). Overweight(OR=0.490,P=0.003),obesity(OR=0.347,P=0.022),and SOFA score(OR=0.930,P=0.024)were independent risk factors of full feeding,while underweight(OR=2.464,P=0.007,) and mechanical ventilation(OR=2.116,P=0.004)were protective factors. Conclusion The gastric residual volume of ICU patients receiving continuous enteral feeding varies regularly,and many patients have not been fully fed,while large gastric residual volume is not an independent risk factor of full feeding. Therefore,patients who are overweight,obese or have greater SOFA score should receive much attention on their enteral feeding.