Abstract: Objective To explore the intervention effect of individualized nutritional support nursing guided by nutritional assessment for patients with severe diseases. Methods A total of 116 patients in ICU were selected and randomly divided into control group(n=58)and observation group(n=58). The control group was conducted with intensive routine nursing of ICU, while the observation group was treated with individualized nutritional support nursing guided by nutrition assessment on the basis of the routine nursing. The changes of physical indexes such as upper arm muscle circumference(MAMC), triceps skinfold thickness(TSF)and body mass index(BMI)as well as blood biochemical and blood routine indexes such as lymphocyte count(LY), hemoglobin(Hb), high-sensitivity C reactive protein(hs-CRP), pre-albumin(PALB), total protein(TP)and plasma albumin(ALB)were observed and compared between two groups. Results After nursing, the levels of TSF, BMI, hs-CRP, PALB, TP, ALB, MAMC, LY and Hb in the observation group were significantly better than those in the control group(P<0.05). The incidence of complications in the observation group was significantly lower than that in the control group(P<0.05). Conclusion For patients with severe diseases, individualized nutritional support nursing guided by nutritional assessment can significantly improve the nutritional status, reduce the incidence of complications and promote recovery of diseases.