Objective The therapeutic effect of nutritional support on patients with chronic critical illness and the effects on the prognosis of production purpose . Methods In our hospital in 2012 February-2013 year in February 61 cases of chronic ill patients as a clinical study ,the nutritional support treatment was analyzed .Re-sults In a week,patients with Alb,the total heat/nitrogen,on nitrogen heat/nitrogen and APACHE Ⅱ score was negative correlation(P<0.05).Conclusion Treatment of nutritional support actively,reasonable,effective for patients with chronic critical illness,can improve the success rate,improve the quality of prognosis.